Chapter 5 Quiz 1 (2nd Secondary Biology)
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Which of the following would be the appropriate stimulus and response for gravitropism?
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Stimulus= Touch; Response= Closure of leaves
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Stimulus= Gravity; Response= stem grows up
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Stimulus= gravity; Response= stem grows towards light
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Stimulus= Light; Response= root grows towards water
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Are you looking for practice questions and answers from class 11, Biology chapter 5, for your exam? Check out this trivia quiz and make your practice level better. This quiz consists of questions from the chapter "Morphology of Flowering Plants." There are two systems present in flowering plants- the root system and the shoot system. A flower has four whorls; See morecalyx, corolla, androecium, and gynoecium. Let's learn about the morphology of flowering plants in detail with this trivia quiz. We hope you secure good marks on this quiz and in your upcoming exam.
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- 2.
All of the following parts of the Mimosa plant would undergo some sort of movement as a result of the plant’s unique response to touch except the -------- .
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Leaflets
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Pulvini
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Stem
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Rachis
Correct Answer
A. StemExplanation
The Mimosa plant has a unique response to touch called thigmonasty, where its leaflets and pulvini (small swollen structures at the base of each leaflet) undergo rapid movement when touched. This movement is a defensive mechanism to protect the plant from potential threats. However, the stem does not undergo any significant movement in response to touch. Therefore, the correct answer is stem.Rate this question:
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- 3.
Which of the following statements is true about the primary pulvinus of a Mimosa plant?
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All its cells are equally sensitive.
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It is found at the tip of the primary rachis.
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It is found below each leaflet.
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When it shrinks, the whole leaf drops down as if the plant wilted.
Correct Answer
A. When it shrinks, the whole leaf drops down as if the plant wilted.Explanation
The primary pulvinus of a Mimosa plant is responsible for the leaf movement. When it shrinks, the whole leaf drops down, giving the appearance that the plant has wilted. This mechanism allows the plant to conserve water and protect itself from potential harm.Rate this question:
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- 4.
Which of the following is correct about the leaves of a Mimosa plant?
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Compound and pinnate with four secondary rachises
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Simple and pinnate with three secondary rachises and one primary rachis
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Compound and pinnate with three secondary rachises and one primary rachis
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Simple and pinnate with four secondary rachises
Correct Answer
A. Compound and pinnate with four secondary rachisesExplanation
The correct answer is compound and pinnate with four secondary rachises. This means that the leaves of a Mimosa plant are composed of multiple leaflets arranged in a feather-like pattern along a central axis (primary rachis). Each leaflet is further divided into smaller leaflets (secondary rachises), with a total of four secondary rachises branching off from the primary rachis.Rate this question:
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- 5.
Which of the following is often associated with the growth rather than the movement?
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Response of Mimosa leaflets to night.
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Response of roots to water.
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Closure of certain flowers at night.
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Capturing of some plants to insects.
Correct Answer
A. Response of roots to water.Explanation
The growth of roots is often associated with their response to water. When roots sense the presence of water, they elongate and grow towards the source of water, allowing the plant to absorb more water and nutrients. This growth response is crucial for the plant's survival and overall development. On the other hand, the other options mentioned in the question involve movement or responses that are not directly related to growth.Rate this question:
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- 6.
From the interaction of hydrotropism with geotropism that took place in the following experiment, we can conclude that......
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The geotropic response of roots became more clear.
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The hydrotropic response of roots became more clear.
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Roots were unresponsive to both stimuli.
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Both hydrotropism and geotropism interacted equally.
Correct Answer
A. The hydrotropic response of roots became more clear.Explanation
Based on the given information, the experiment showed that the hydrotropic response of roots became more clear. This suggests that the roots were more responsive to the stimulus of water compared to the stimulus of gravity (geotropism). The other options are not supported by the information given in the question.Rate this question:
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- 7.
A vine plant brushes against a fence and wraps itself around the fence. To what stimulus is the plant responding? [Brushes against = pass by and touch]
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Phototropism
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Hydrotropism
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Haptootropism
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Gravitropism
Correct Answer
A. HaptootropismExplanation
The correct answer is Haptootropism. Haptootropism is a type of tropism in which a plant responds to touch or contact stimuli. In this case, the vine plant is responding to the stimulus of brushing against the fence by wrapping itself around the fence.Rate this question:
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- 8.
Which of the following is true about the waking movement of a Mimosa plant?
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Water moves to the cells in the lower half of primary pulvini, causing these cells to become turgid.
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Water moves to the cells on the lower side of secondary rachises, causing them to become turgid.
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Water moves outside of the cells on the lower side of primary rachis, causing them to shrink.
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Water moves to the cells in the lower and upper halves of primary pulvini, causing them to become turgid.
Correct Answer
A. Water moves to the cells in the lower half of primary pulvini, causing these cells to become turgid.Explanation
Water moves to the cells in the lower half of primary pulvini, causing these cells to become turgid. This is true because the movement of water in the Mimosa plant is responsible for the plant's ability to fold and unfold its leaves in response to stimuli. The primary pulvini are specialized structures at the base of each leaflet that control leaf movement. When water moves into the cells in the lower half of the primary pulvini, it causes these cells to swell and become turgid, which results in the folding or closing of the leaf.Rate this question:
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- 9.
Changes in plants environment that cause a response
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Tropism
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Hormone
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Stimuli
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Auxin
Correct Answer
A. StimuliExplanation
Stimuli refers to changes in the plants' environment that trigger a response. This can include factors such as light, temperature, gravity, and touch. Plants have the ability to sense these stimuli and respond accordingly, for example by growing towards a light source or bending away from gravity. Tropism is the specific growth response of a plant towards or away from a stimulus, such as phototropism (response to light) or gravitropism (response to gravity). Hormones, such as auxin, play a role in regulating these growth responses. Therefore, while all the options are related to plant responses, stimuli is the most general term that encompasses the various factors that can cause a response in plants.Rate this question:
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- 10.
A growing plant was exposed to light from one side for a while. Which plant represents the growth rate of the growing tip cells of the part away of light in the stem of this plant?
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A
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B
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C
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D
Correct Answer
A. AExplanation
The correct answer is A because it shows that the growth rate of the growing tip cells of the part away from light in the stem of the plant is slower compared to the other options. This suggests that light is necessary for the optimal growth of the plant, and without it, the growth rate is reduced.Rate this question:
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- 11.
The attitude of Venus Flytrap plant towards insects is described as -------.
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Nastic Movement
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Negative Gravitropism
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Haptotropism
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Hydrotropism
Correct Answer
A. Nastic MovementExplanation
The attitude of Venus Flytrap plant towards insects is described as nastic movement. Nastic movement refers to the non-directional response of a plant to a stimulus, such as the closing of the Venus Flytrap's leaves when an insect touches its trigger hairs. This movement is not dependent on the direction of the stimulus, but rather a general response to it.Rate this question:
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- 12.
When the tip of Oat coleoptile is cut off, it loses its ability to bend towards light. This was proved by. …..
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Charles Darwin
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Went
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Herman
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Boysen Jensen
Correct Answer
A. Boysen JensenExplanation
Boysen Jensen proved that when the tip of Oat coleoptile is cut off, it loses its ability to bend towards light.Rate this question:
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- 13.
Pulvinus is divided into two parts, extensor (lower half) and flexor (upper half). The diagram below, illustrates the size of the upper and lower cells in two different conditions (sleeping movement and wake up movement). During the leaf opening (in charge of osmosis), ions such as K+ and Cl− actively influx to the ------------.
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Flexor
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Extensor
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Flexor and extensor
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None of them
Correct Answer
A. ExtensorExplanation
During the leaf opening movement, ions such as K+ and Cl- actively influx to the extensor.Rate this question:
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- 14.
What happens by the removal of the apical bud from a plant stem?
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The plant grows rapidly.
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The plant grows slowly.
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The plant wilts and dies.
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The lateral buds wake up and start growing.
Correct Answer
A. The lateral buds wake up and start growing.Explanation
When the apical bud is removed from a plant stem, it removes the inhibitory effect of the apical dominance hormone, auxin. This allows the lateral buds to become active and start growing. The lateral buds are usually suppressed by the apical bud, but with its removal, they are able to grow and develop into branches. This leads to increased branching and growth in the plant.Rate this question:
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- 15.
A decapitated plant exposed to unilateral light…
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Bends away from source of illumination.
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Bends towards the source of light.
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Shows zigzag curvature.
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Does not show bending movement.
Correct Answer
A. Does not show bending movement.Explanation
When a plant is decapitated, it loses its apical dominance, which is the control exerted by the growing tip over the lateral buds. Without apical dominance, the lateral buds are free to grow and elongate, leading to the bending movement of the plant towards the source of light. However, a decapitated plant does not have a growing tip to influence the growth of lateral buds, so it does not show any bending movement towards the source of light.Rate this question:
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- 16.
The movement of sunflower in accordance with the path of sun is due to...
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Heliotropism
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Geotropism
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Chemotropism
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Hydrotropism
Correct Answer
A. HeliotropismExplanation
The movement of sunflowers in accordance with the path of the sun is due to heliotropism. Heliotropism is the ability of plants to track the movement of the sun throughout the day. Sunflowers are known for their heliotropic behavior, as they face east in the morning and follow the sun as it moves across the sky, eventually facing west in the evening. This movement is controlled by specialized cells in the stem that respond to light and help the plant optimize its exposure to sunlight for photosynthesis.Rate this question:
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- 17.
The figure below represents some parts of the Mimosa plant. What happens to these parts at night?
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Part (Y) hangs down so part (X) shrinks
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Part (X) shrinks so part (Y) hangs down
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Part (X) shrinks so water diffuses to it from part (Y)
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Water diffuses from part (Y) so part (X) shrinks
Correct Answer
A. Part (X) shrinks so part (Y) hangs down -
- 18.
The root of a plant growing down, then this phenomenon is a...
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Geotropism
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Phototropism
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Haptotropism
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Hydrotropism
Correct Answer
A. GeotropismExplanation
Geotropism is the correct answer because it refers to the growth or movement of a plant in response to gravity. When the root of a plant grows downwards, it is exhibiting positive geotropism, as it is growing in the direction of gravity. This phenomenon allows the roots to anchor the plant in the soil and absorb water and nutrients effectively. Phototropism refers to the growth or movement of a plant in response to light, haptotropism refers to the growth or movement of a plant in response to touch, and hydrotropism refers to the growth or movement of a plant in response to water.Rate this question:
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- 19.
....... is an example of the movement of a plant part which is very quick and can be observed easily.
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Touch movement in the leaves of Mimosa plant.
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Movement of stem towards light.
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Movement of roots away of light.
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Movement of sunflower towards sun.
Correct Answer
A. Touch movement in the leaves of Mimosa plant.Explanation
The correct answer is touch movement in the leaves of the Mimosa plant. This plant exhibits a rapid response to touch, where its leaves fold up or droop when touched. This movement can be easily observed and is a clear example of a plant part moving quickly in response to a stimulus.Rate this question:
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- 20.
Plants respond to their environments. Such responses are known as tropisms. Which of the following is not an example of a tropism?
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Plant coiling around an object that it touches
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Leaves droop down when temperature changes
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Plant turning as the sun moves from east to west.
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Plant closing its leaves at night
Correct Answer
A. Plant closing its leaves at nightExplanation
The closing of leaves at night is an example of nyctinasty, not a tropism. Tropisms are directional growth responses of plants to external stimuli, such as light, gravity, or touch. The other options mentioned in the question are examples of different types of tropisms: thigmotropism (plant coiling around an object), thermotropism (leaves drooping down when temperature changes), and phototropism (plant turning as the sun moves).Rate this question:
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- 21.
In the experiment shown in the figure below, why does coleoptile (A) bend while coleoptile (B) does not bend?
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Because auxins can diffuse through mica block but not though gelatin block.
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Because auxins can diffuse through both mica and gelatin blocks.
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Because auxins can’t diffuse through mica or gelatin blocks.
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Because auxins can diffuse through gelatin block but not through mica block.
Correct Answer
A. Because auxins can diffuse through gelatin block but not through mica block.Explanation
The figure shows an experiment where two coleoptiles, A and B, are placed next to mica and gelatin blocks. The question asks why coleoptile A bends while coleoptile B does not bend. The correct answer is that auxins, which are plant hormones responsible for bending growth, can diffuse through the gelatin block but not through the mica block. This suggests that the presence of auxins on one side of the coleoptile, diffusing through the gelatin block, causes it to bend towards that side. However, since auxins cannot diffuse through the mica block, coleoptile B does not receive auxins and therefore does not bend.Rate this question:
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- 22.
Which side contains more auxin (A), (B), (C) or (D)?
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A
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B
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C
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D
Correct Answer
A. DExplanation
The correct answer is D because auxin is typically synthesized in the apical meristem and then transported downwards through the plant. In this diagram, side D is located at the bottom of the plant, indicating that it is likely to contain a higher concentration of auxin compared to sides A, B, and C.Rate this question:
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- 23.
The figure below shows that on the primary root, smaller lateral roots known as the secondary roots are formed. Tertiary roots are considered the branches of the secondary roots. This branching is essential for the absorption of water, promoting the uptake of nutrients and help to fix the plant securely in the soil. Which of the following is correct about tertiary roots?
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Tertiary roots are positively geotropic
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Tertiary roots are orientated at an angle to the line of action of the stimulus
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Tertiary roots are negatively geotropic
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There is no geotropic sensitivity in tertiary roots
Correct Answer
A. There is no geotropic sensitivity in tertiary rootsExplanation
Tertiary roots are not sensitive to geotropism, which is the response of plant roots to gravity. Geotropism causes roots to grow in the direction of gravity, either positively (towards gravity) or negatively (away from gravity). Since tertiary roots do not exhibit geotropic sensitivity, they do not respond to gravity and do not grow in a particular direction in response to it.Rate this question:
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- 24.
The following diagram illustrates the effect of auxins on a structure (X) in a certain plant. What does the structure (X) represent?
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Root
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Stem
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Underground stem
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Leaf
Correct Answer
A. RootExplanation
The diagram shows the effect of auxins on a structure, which is represented by X. Auxins are plant hormones that promote root growth. Therefore, the structure X in the diagram represents the root of the plant.Rate this question:
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- 25.
If a plant grows toward a light source, then it is said to be displaying _____?
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Negative phototropism
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Positive phototropism
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Negative geotropism
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Positive hydrotropisn
Correct Answer
A. Positive phototropismExplanation
Positive phototropism is the correct answer because it refers to the phenomenon where a plant grows towards a light source. Plants exhibit positive phototropism as they bend or grow towards the light in order to maximize their exposure to sunlight for photosynthesis.Rate this question:
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- 26.
Where is the auxin hormone made in a plant stem?
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At the tip of the stem.
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In the petals of flowers.
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In the leaves of the stem.
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Beneath the tip of the stem.
Correct Answer
A. At the tip of the stem.Explanation
Auxin hormone is produced at the tip of the stem in plants. This hormone plays a crucial role in plant growth and development, including cell elongation, root formation, and phototropism. It is synthesized in the apical meristem, which is present at the tip of the stem. From there, it is transported downwards to other parts of the plant, where it regulates various physiological processes.Rate this question:
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- 27.
The growth of a pollen tube towards the ovule is caused by…
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Phototropism
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Chemotropism
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Hydrotropism
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Geotropism
Correct Answer
A. ChemotropismExplanation
Chemotropism is the correct answer because the growth of a pollen tube towards the ovule is guided by chemical signals released by the ovule. The pollen tube is attracted to these chemicals, allowing it to navigate towards the ovule and facilitate fertilization. Phototropism is the growth of a plant towards light, which is not relevant in this context. Hydrotropism is the growth of a plant towards water, and geotropism is the growth of a plant in response to gravity, neither of which are involved in the growth of a pollen tube towards the ovule.Rate this question:
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- 28.
Look at the figure carefully then choose the correct answer: Buttercup plant (Ranunculus adoneus) grows in north-east Siberia. The flowers of the snow buttercup face east early in the morning and south‐west by the mid‐afternoon where they remain facing south‐west till the next morning. Most likely this is a response to which stimulus?
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Daily rise and fall in temperature.
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Daily rainfall patterns.
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Sun passing through the sky.
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Physical contact with flying butterflies .
Correct Answer
A. Sun passing through the sky.Explanation
The correct answer is "Sun passing through the sky." This is because the flowers of the snow buttercup face east early in the morning and south-west by the mid-afternoon, following the path of the sun as it moves across the sky. This suggests that the flowers are responding to the stimulus of the sun's movement, orienting themselves to maximize exposure to sunlight for photosynthesis. The other options, such as daily rise and fall in temperature, daily rainfall patterns, and physical contact with flying butterflies, do not align with the specific behavior described in the question.Rate this question:
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- 29.
What would happen when lighting a plant from below the leaves as in figure (Lighting a plant from beneath)?
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The stem would grow away of the light
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The root would exhibit negative phototropism
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The stem would respond postively to gravity
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The root would exhibit positive phototropism
Correct Answer
A. The stem would respond postively to gravityExplanation
When lighting a plant from below the leaves, the stem would respond positively to gravity. This is because the stem exhibits gravitropism, which is the growth or movement of a plant in response to gravity. In this case, the stem would grow in the opposite direction of the light source, which is downward, due to the influence of gravity.Rate this question:
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- 30.
....... is an example of the movement of a plant part which is caused by the migration of water.
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Hydrotropism.
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Geotropism.
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Sleeping movement.
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Phototropism.
Correct Answer
A. Sleeping movement. -
- 31.
When a plant root is subjected underground to water from only one direction. Which of the following graphs shown below, represents the correct rate of growth for the root parts?
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A
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B
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C
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D
Correct Answer
A. CExplanation
The correct rate of growth for the root parts when subjected to water from only one direction would be represented by graph C. This graph shows a gradual increase in growth over time, indicating that the root is receiving a steady supply of water. The other graphs either show no growth or inconsistent growth, which would not be expected when water is provided from one direction.Rate this question:
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- 32.
An example of ______ is when a plant starts to coil around another type of plant.
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Positive geotropism
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Negative phototropism
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Positive haptotropism
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Positive hydrotropism
Correct Answer
A. Positive haptotropismExplanation
Positive haptotropism is the correct answer because haptotropism refers to the directional growth or movement of an organism in response to touch or contact stimuli. In this example, the plant is coiling around another type of plant in response to physical contact, which is an example of positive haptotropism.Rate this question:
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- 33.
Which figure shows the correct position of each of the parts (A) and (B) according to the stimulus...
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(1)
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(2)
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(3)
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None of them.
Correct Answer
A. (2) -
- 34.
Why is the folding up of the leaves of a sensitive plant on touching with a finger not a tropism?
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Because there is no change in the growth of the plant.
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Because the plant moves in all directions.
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Because auxins accumulate on both sides in unequal ratios.
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Because folding up of leaves is a touch-induced movement.
Correct Answer
A. Because there is no change in the growth of the plant.Explanation
The folding up of the leaves of a sensitive plant on touching with a finger is not a tropism because there is no change in the growth of the plant. Tropism refers to the directional growth response of a plant towards or away from a stimulus, such as light or gravity. In this case, the folding up of the leaves is a touch-induced movement, but it does not involve any growth or change in the overall direction of growth of the plant.Rate this question:
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- 35.
Opening and closing of flowers represents a kind of...
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Autonomic movement
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Nutation (swaying motion)
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Tropic movement
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Nastic movement
Correct Answer
A. Nastic movementExplanation
Nastic movement refers to the non-directional response of a plant to a stimulus. In the case of opening and closing of flowers, this movement is not dependent on the direction of the stimulus, but rather on the internal factors of the plant. The flowers open and close in response to changes in light, temperature, or other environmental factors. This movement allows the plant to regulate its reproductive processes and optimize pollination.Rate this question:
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- 36.
A growth movement of a plant part in response to an external stimulus in which the direction of stimulus determines the direction of response is called
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Sleeping movement
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Turgidity
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Tropism
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Touch movement
Correct Answer
A. TropismExplanation
Tropism is the correct answer because it refers to the growth movement of a plant part in response to an external stimulus, where the direction of the stimulus determines the direction of the plant's response. This can include movements such as phototropism (response to light), geotropism (response to gravity), and hydrotropism (response to water). Sleeping movement, turgidity, and touch movement do not accurately describe this specific type of growth response.Rate this question:
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- 37.
Which part of the plant responds positively to gravity?
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Xylem
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Leaves
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Roots
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Stem
Correct Answer
A. RootsExplanation
Roots respond positively to gravity by growing downwards. This is known as geotropism or gravitropism. The roots have specialized cells called statocytes that contain dense starch grains, which settle under the influence of gravity. This helps the roots sense the direction of gravity and grow in the opposite direction, towards the center of the Earth. This allows the roots to anchor the plant in the soil and absorb water and nutrients from the ground.Rate this question:
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- 38.
Which diagram shows a negative geotropism (A), (B), (C) or (D)?
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A
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B
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C
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D
Correct Answer
A. DExplanation
Diagram D shows a negative geotropism because the plant is growing in an upward direction, against the force of gravity. This can be observed by the stem and leaves extending vertically upwards. In contrast, diagrams A, B, and C show positive geotropism, as the plants are growing in the direction of gravity, with their stems and leaves bending downwards.Rate this question:
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- 39.
In the experiment shown in the figure below, what will happen to each of the three coleoptiles after several hours of the experiment?
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(1) will not bend / (2) and (3) will bend towards light
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(1) and (2) will bend towards light / (3) will not bend
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(1) will bend away of light / (2) and (3) will bend towards light
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(1) and (2) will not bend / (3) will bend towards light
Correct Answer
A. (1) and (2) will not bend / (3) will bend towards lightExplanation
Based on the information given in the question, it can be inferred that the three coleoptiles will respond differently to the experiment. Coleoptile (1) will not bend towards the light, while coleoptile (2) will also not bend towards the light. However, coleoptile (3) will bend towards the light. Therefore, the correct answer is that (1) and (2) will not bend, while (3) will bend towards the light.Rate this question:
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- 40.
Which parts of the plant display positive phototropism?
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Roots and stem
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Leaves and stem
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Leaves and roots
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All the above
Correct Answer
A. Leaves and stemExplanation
Phototropism is the growth or movement of an organism towards or away from light. Positive phototropism refers to the growth towards light. In plants, the stem and leaves are the parts that display positive phototropism. The stem grows towards the light source to maximize light absorption for photosynthesis, while the leaves adjust their position to receive optimal sunlight. The roots, on the other hand, exhibit negative phototropism, growing away from light sources, as they are responsible for anchoring the plant and absorbing water and nutrients from the soil.Rate this question:
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- 41.
The pad-like swelling at the base of each leaf of a sensitive plant is called
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Rachis
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Auricle
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Foliage
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Pulvini
Correct Answer
A. PulviniExplanation
The pad-like swelling at the base of each leaf of a sensitive plant is called pulvini. Pulvini are specialized structures found in certain plants that allow for rapid leaf movement. They are responsible for the plant's ability to fold its leaves in response to touch or other stimuli. This folding action is a defense mechanism that helps protect the plant from potential harm. The pulvini contain motor cells that respond to electrical signals, causing the leaves to move.Rate this question:
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- 42.
In the experiment shown in the figure below what will happen to the two coleoptiles (1) and (2) after some hours of the experiment? (the coleoptiles are not subjected to light).
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In (1), A bends towards B / In (2), A and B grow vertically upwards
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In (1), B bends towards A / In (2), A and B grow vertically upwards
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In (1), A bends towards B / In (2), B bends towards A
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In (1) A and B stop growth / In (2) B bends towards A
Correct Answer
A. In (1), B bends towards A / In (2), A and B grow vertically upwardsExplanation
In the experiment, coleoptile (1) bends towards coleoptile (2) because coleoptile (1) is subjected to a unilateral light source. This bending is known as phototropism, where plants grow towards the light source. Coleoptile (2) grows vertically upwards because it is not subjected to any light source. This is the natural growth pattern of plants in the absence of light. Therefore, after some hours of the experiment, coleoptile (1) will bend towards coleoptile (2), and coleoptile (2) will grow vertically upwards.Rate this question:
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- 43.
What happens if the tip of oat coleoptile is separated by a glass sheet, then it is exposed to light from one direction?
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Geotropism will take place
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Hydrotropism will take place
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Nothing will happen
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Phototropism will take place
Correct Answer
A. Nothing will happenExplanation
If the tip of the oat coleoptile is separated by a glass sheet and then exposed to light from one direction, nothing will happen. This is because the tip of the coleoptile is responsible for sensing light and initiating phototropism, which is the growth or movement of an organism in response to light. However, when the tip is separated by a glass sheet, it is unable to detect the light and therefore cannot initiate phototropism.Rate this question:
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- 44.
A student wanted to investigate the effect of light on the growth of cress seedlings. The student had three pots of seedlings grown in different conditions. One of the pots was placed with light from above. The second was placed in a cupboard with no light, while the third one was placed in a window with light from one direction only. The image shows the seedlings at the end of the investigation. What is the response shown by the cress seedlings in Pot (2)?
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Negative geotropism
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Negative phototropism
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Positive geotropism
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Positive phototropism
Correct Answer
A. Positive phototropismExplanation
The cress seedlings in Pot (2) were placed in a cupboard with no light. As a result, they grew straight up towards the only available light source, which is the opening of the cupboard. This is an example of positive phototropism, where the plants grow towards the light.Rate this question:
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- 45.
In an experiment to prove the role of auxins in plant growth, IAA was added gradually to the soil where Bean plant seedling grows. Which of the following graphs represent the effect of auxin on the growth of the growing tip cells of both the stem and the root of this seedling?
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A
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B
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C
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D
Correct Answer
A. BExplanation
Graph B represents the effect of auxin on the growth of the growing tip cells of both the stem and the root of the seedling. This is because the graph shows an increase in growth rate initially, followed by a decrease in growth rate. This is consistent with the known effects of auxins, which promote cell elongation and division in the early stages of growth, but inhibit growth at higher concentrations.Rate this question:
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- 46.
High concentrations of auxins causes
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Elongation of root cells
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Inhibition of elongation of root cells
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Elongation of both root and stem cells
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Inhibition of elongation of stem cells
Correct Answer
A. Inhibition of elongation of root cellsExplanation
High concentrations of auxins inhibit the elongation of root cells. Auxins are plant hormones that regulate various growth processes, including cell elongation. At low concentrations, auxins promote cell elongation, but at high concentrations, they have an inhibitory effect. This is because high levels of auxins can disrupt the balance of other hormones and signaling pathways involved in cell growth, leading to the inhibition of root cell elongation.Rate this question:
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- 47.
In the experiment shown in the figure below, what will happen to each of coleoptiles (A) and (B) after leaving the experiment for several hours?
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(A) will not bend / (B) will bend towards light
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Both (A) and (B) will bend towards light
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Both (A) and (B) will not bend
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(A) will bend towards light / (B) will not bend
Correct Answer
A. (A) will not bend / (B) will bend towards lightExplanation
In the experiment, the coleoptiles (A) and (B) are exposed to light. Coleoptile (A) will not bend because it has been covered with an opaque cap, preventing light from reaching it. On the other hand, coleoptile (B) is exposed to light, causing it to bend towards the light source. This is known as phototropism, a plant's growth response to light. Therefore, the correct answer is that (A) will not bend, while (B) will bend towards light.Rate this question:
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- 48.
A student wanted to find out where the hormone that caused the response to directional light was found. The student had two growing plant shoots. He placed them both in a window with light coming from one direction. Describe a method the student could use to show that the hormone was found in the tip of the plant shoot.
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Remove the tip from one of the plant shoots and leave the other then measure the changes in growth.
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Remove the tip from both plant shoots then measure the changes in growth.
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Put one plant in light while the other in dark then measure the changes in growth.
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Put one plant in a light-proof box while the other in a place where light falls from one direction then measure the changes in growth.
Correct Answer
A. Remove the tip from one of the plant shoots and leave the other then measure the changes in growth.Explanation
By removing the tip from one of the plant shoots and leaving the other intact, the student can observe the changes in growth. If the hormone responsible for the response to directional light is found in the tip, the plant shoot with the removed tip would not show the expected response to light, while the intact shoot would continue to respond. This would indicate that the hormone is indeed located in the tip of the plant shoot.Rate this question:
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- 49.
In which of the following diagrams does phototropism enhance hydrotropism of the root?
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A
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B
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C
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D
Correct Answer
A. DExplanation
In diagram D, the root is bending towards the water source (hydrotropism) and also towards the light source (phototropism). This suggests that phototropism is enhancing the hydrotropism of the root, as it is guiding the root towards both the light and water sources.Rate this question:
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Jul 11, 2023Quiz Edited by
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Jul 28, 2019Quiz Created by
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