1.
The layer of gas covering the earth is called:
Correct Answer
A. Atmosphere
Explanation
The layer of gas surrounding the Earth is known as the atmosphere. It is composed of various gases, such as nitrogen, oxygen, carbon dioxide, and trace amounts of other elements. The atmosphere plays a crucial role in protecting and sustaining life on Earth by regulating temperature, supporting weather patterns, and filtering harmful radiation from the sun.
2.
The speed of light has been calculated to be 186,000.
Correct Answer
C. Miles per second
Explanation
The speed of light measured in miles per second is 186,000 mi/s. In meters per second, the speed of light is 3x108 m/s.
3.
A distance of one mile is about:
Correct Answer
D. 1.6 kilometers
Explanation
A distance of one mile is approximately equal to 1.6 kilometers.
4.
The largest object in the solar system is:
Correct Answer
A. A star
Explanation
A star is the largest object in the solar system. Stars are massive, luminous spheres of plasma held together by gravity. They emit light and heat due to the nuclear reactions occurring in their cores. Planets, asteroids, and meteors are much smaller in comparison. Planets are celestial bodies that orbit around a star, asteroids are rocky objects that orbit the sun, and meteors are small particles that burn up upon entering a planet's atmosphere. Therefore, the correct answer is a star.
5.
Which of the following is most responsible for erosion?
Correct Answer
C. Rivers
Explanation
Rivers are most responsible for erosion because they constantly flow and carry sediment, such as rocks, sand, and soil, downstream. As rivers move, they erode the land by wearing away rocks and soil, creating channels and valleys. The force of the water, combined with the sediment it carries, can break down and transport materials over long distances. This process of erosion by rivers is a major factor in shaping the Earth's surface and creating landforms such as canyons and river deltas.
6.
Which of the following is most responsible for earthquakes?
Correct Answer
B. An imbalance in the crust
Explanation
The correct answer is an imbalance in the crust. Earthquakes occur when there is a sudden release of energy in the Earth's crust, which causes the ground to shake. This release of energy is typically caused by the movement of tectonic plates, which are large sections of the Earth's crust that float on the semi-fluid mantle below. When these plates move past each other, they can become stuck due to friction. When the stress on the stuck section of the fault becomes too great, it is suddenly released, causing an earthquake. The magnetic field, speed of light, and atmosphere do not play a direct role in causing earthquakes.
7.
When a scientist uses the process of reasoning, it means that he
Correct Answer
C. Makes inferences on the basis of observations
Explanation
When a scientist uses the process of reasoning, it means that he makes inferences on the basis of observations. This means that the scientist uses logical thinking and analysis to draw conclusions from the data and evidence gathered through observations. Reasoning allows scientists to make connections, identify patterns, and make educated guesses or predictions based on the information they have collected. It is an essential step in the scientific method and helps scientists to understand and explain the natural world.
8.
An instrument that is used to map the ocean floor is called?
Correct Answer
B. A SONAR
Explanation
SONAR stands for Sound Navigation and Ranging. It is an instrument that uses sound waves to map and measure the ocean floor. By emitting sound waves and measuring the time it takes for them to bounce back, SONAR can create detailed maps of underwater terrain. This technology is widely used in oceanography, marine exploration, and navigation to study and understand the ocean floor.
9.
When scientists refer to the hydrosphere, they mean:
Correct Answer
D. Water of the earth
Explanation
The hydrosphere refers to all the water on Earth, including oceans, lakes, rivers, groundwater, and even water vapor in the atmosphere. It is an essential component of Earth's system and plays a crucial role in various processes such as weather, climate, and the water cycle. Therefore, when scientists refer to the hydrosphere, they are specifically referring to the water present on Earth.
10.
Chemical elements that are usually present in only very small amounts are called?
Correct Answer
B. Trace elements
Explanation
Chemical elements that are usually present in only very small amounts are called trace elements. These elements are essential for the proper functioning of organisms, even though they are required in very small quantities. Radio elements refer to elements that are radioactive, while scarce elements simply indicate elements that are not abundant. Therefore, trace elements is the correct answer in this context.
11.
The Milky Way is a
Correct Answer
C. Galaxy
Explanation
The Milky Way is a galaxy. A galaxy is a large system of stars, gas, and dust held together by gravity. The Milky Way is the galaxy that contains our solar system and is made up of billions of stars, as well as other celestial objects. It is a spiral-shaped galaxy and is just one of many galaxies in the universe.
12.
The brightest star in the sky other than our sun is:
Correct Answer
C. Sirius
Explanation
Sirius is the correct answer because it is the brightest star in the sky other than our sun. It is located in the constellation Canis Major and is known for its striking brightness and white-blue color. Sirius is also a binary star system, consisting of a main sequence star and a white dwarf companion. Its brightness and visibility make it a prominent star in the night sky and easily recognizable to observers.
13.
A scale of temperature that uses absolute zero, the lowest possible temperature for its zero points is called
Correct Answer
B. Kelvin scale
Explanation
The Kelvin scale is a temperature scale that starts at absolute zero, which is the lowest possible temperature. It is based on the concept of absolute temperature, where zero Kelvin represents the complete absence of thermal energy. This scale is commonly used in scientific and engineering applications, particularly in physics and chemistry. The Fahrenheit scale and Celsius scale are both relative scales that are based on the freezing and boiling points of water, while the Cepheid scale does not exist.
14.
The force of attraction between the earth and the moon is called
Correct Answer
A. Gravity
Explanation
Gravity is the force of attraction between two objects with mass. In this case, it refers to the force of attraction between the Earth and the Moon. This force is responsible for keeping the Moon in orbit around the Earth and is also responsible for tides on Earth. Inertia refers to an object's resistance to change in motion, relativity is a theory of physics, and equivalence is a concept in mathematics. None of these options accurately describe the force of attraction between the Earth and the Moon.
15.
The moon’s gravity is _____________ that of the earth’s.
Correct Answer
D. 1/6
Explanation
The moon's gravity is 1/6th that of the earth's. This means that the gravitational force exerted by the moon on an object is only 1/6th of the gravitational force exerted by the earth on the same object. This is why astronauts on the moon can jump higher and objects weigh less compared to on earth.
16.
Which of the following did Sir Isaac Newton discover?
Correct Answer
C. Law of gravitation
Explanation
Sir Isaac Newton discovered the law of gravitation. This law states that every object in the universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Newton's discovery of this law revolutionized our understanding of the physical world and laid the foundation for modern physics.
17.
Why is it warmer in regions near the equator?
Correct Answer
B. Regions near the equator get vertical rays from the sun.
Explanation
Regions near the equator get vertical rays from the sun. This means that the sun's rays hit the Earth's surface at a more direct angle, resulting in a higher concentration of solar energy in that area. As a result, the temperature in regions near the equator is warmer compared to other regions where the sun's rays hit the surface at a more oblique angle.
18.
What is the important animal hormone responsible for the control of glucose levels in the blood?
Correct Answer
D. Insulin
Explanation
Insulin is the important animal hormone responsible for the control of glucose levels in the blood. It is produced by the pancreas and helps regulate the amount of glucose in the bloodstream. Insulin allows cells to absorb glucose and use it for energy, thus lowering blood sugar levels. Without sufficient insulin, glucose levels can become too high, leading to conditions like diabetes. Thyroxine, cortisol, and prostaglandin are not directly involved in the control of glucose levels in the blood.
19.
A 1,000-kilogram car traveling with a velocity of +20. meters per second decelerates uniformly at -5.0 meters per second2 until it comes to rest. What is the total distance the car travels as it decelerates to rest?
Correct Answer
C. 40 m
Explanation
The car is initially traveling at a velocity of +20 meters per second. It decelerates uniformly at a rate of -5.0 meters per second squared until it comes to rest. The total distance traveled can be calculated using the equation:
distance = (initial velocity^2 - final velocity^2) / (2 * acceleration)
Plugging in the values, we get:
distance = (20^2 - 0^2) / (2 * -5) = 400 / -10 = -40
Since distance cannot be negative, we take the absolute value, which gives us 40 meters. Therefore, the total distance the car travels as it decelerates to rest is 40 meters.
20.
What yellowish-orange compound belonging to the vitamin B complex is used to treat pernicious anemia? It is synthesized in the intestinal bacteria and occurs in green plants, fresh fruit, liver, and yeast. Its formula is C19H19N7O6.
Correct Answer
D. Folic acid
Explanation
Folic acid is a yellowish-orange compound belonging to the vitamin B complex that is used to treat pernicious anemia. It is synthesized in the intestinal bacteria and occurs in green plants, fresh fruit, liver, and yeast. Its chemical formula is C19H19N7O6.
21.
The reaction 2H2O(l) --> 2H2O(g) + O2(g) is forced to occur by use of an externally applied electric current. This procedure is called
Correct Answer
C. Electrolysis
Explanation
The given reaction involves the conversion of liquid water to gaseous water and oxygen gas, which can be achieved by the application of an externally applied electric current. This process is known as electrolysis, where the electric current is used to break down the water molecules into their constituent elements. Neutralization involves the reaction between an acid and a base to form a salt and water. Esterification is the formation of an ester by the reaction between an alcohol and an acid. Hydrolysis is the breakdown of a compound by reaction with water. None of these processes involve the use of an electric current to force the reaction to occur.
22.
A student calculated the percent by mass of water in a sample of BaCl2 * H2O to be 16.4% but the accepted value is 14.8%. What was the student’s percent error?
Correct Answer
C. (1.6/14.8)*100%
Explanation
The student's percent error can be calculated by taking the absolute value of the difference between the student's calculated value and the accepted value, dividing it by the accepted value, and then multiplying by 100%. In this case, the student's percent error would be (1.6/14.8)*100%.
23.
The symmetrical structure of the CH4 molecule is due to the fact that the four single bonds between carbon and hydrogen atoms are directed toward the corners of a:
Correct Answer
B. Tetrahedron
Explanation
The symmetrical structure of the CH4 molecule is due to the fact that the four single bonds between carbon and hydrogen atoms are directed toward the corners of a tetrahedron. This means that the molecule has a three-dimensional shape with four identical triangular faces, where each hydrogen atom occupies one corner of the tetrahedron and is equidistant from the carbon atom. This arrangement ensures that the molecule is symmetrical and balanced.
24.
How much work is done on a downhill skier by an average braking force of 9.8 X 102 newtons to stop her in a distance of 10 meters?
Correct Answer
D. 9.8 X 10^3 J
Explanation
The work done on the downhill skier can be calculated using the formula: work = force x distance. In this case, the force is given as 9.8 X 10^2 newtons and the distance is given as 10 meters. By multiplying these values together, we get the work done as 9.8 X 10^3 J.
25.
What is the absence of measurable electrical resistance in certain substances at temperatures close to zero degrees Kelvin?
Correct Answer
D. Superconductivity
Explanation
Superconductivity refers to the absence of measurable electrical resistance in certain substances at temperatures close to zero degrees Kelvin. This phenomenon allows for the flow of electric current without any loss of energy, making superconductors highly efficient for various applications.
26.
What do you call the phylum of marine and freshwater invertebrates which live permanently attached to rocks and other surfaces? Its body is hollow and consists of an aggregation of millions of single-celled organisms.
Correct Answer
C. Porifera
Explanation
Porifera is the correct answer because it is the phylum of marine and freshwater invertebrates that live permanently attached to rocks and other surfaces. The body of Porifera is hollow and consists of an aggregation of millions of single-celled organisms.
27.
What do you call a liquid with a high content of nitrogen, antibodies and vitamins secreted from mammary glands just after giving birth, and prior to the flow of proper milk?
Correct Answer
B. Colostrum
Explanation
Colostrum is the term used to describe the liquid with a high content of nitrogen, antibodies, and vitamins secreted from mammary glands just after giving birth, and prior to the flow of proper milk. It is a crucial substance for newborns as it provides essential nutrients and antibodies that help boost their immune system.
28.
What do you call the reactions in which the hydrogen ion of an acid and the hydroxide ion of a base unite to form water?
Correct Answer
D. Neutralization
Explanation
The reactions in which the hydrogen ion (H⁺) of an acid and the hydroxide ion (OH⁻) of a base unite to form water (H₂O) are called neutralization reactions. These reactions are a fundamental concept in chemistry and are often represented by chemical equations in the form:
Acid + Base → Water + Salt
In a neutralization reaction, the acidic and basic properties are neutralized, leading to the formation of water and a salt. This process typically results in a solution with a pH closer to 7, which is considered neutral on the pH scale.
29.
What term to the part of the nitrogen cycle where nitrogen compounds are formed by certain bacteria from the free nitrogen in the air?
Correct Answer
A. Fixation of Atmospheric Nitrogen
Explanation
Fixation of Atmospheric Nitrogen refers to the process in the nitrogen cycle where certain bacteria convert free nitrogen in the air into nitrogen compounds. This process is essential for making nitrogen available to plants and other organisms in the ecosystem. Denitrification, nitrate leaching from soil, and release of NH4 by decomposition are other processes in the nitrogen cycle, but they do not specifically involve the formation of nitrogen compounds from free nitrogen in the air.
30.
Which lustrous, white metal conducts heat and electricity most easily and is highly valued for ornamental and industrial use?
Correct Answer
D. Silver
Explanation
The lustrous, white metal that conducts heat and electricity most easily and is highly valued for ornamental and industrial use is silver. Silver is known for its excellent electrical and thermal conductivity, which makes it essential in various industrial applications, including electronics and the production of conductive coatings. It is also highly valued for its decorative and ornamental uses, including jewelry and silverware.
31.
Which two metals make-up brass?
Correct Answer
C. Copper and zinc
Explanation
Brass is an alloy made up of copper and zinc. Copper is the main component of brass, providing its characteristic reddish-brown color and malleability. Zinc is added to copper to improve its strength and hardness, as well as to enhance its corrosion resistance. The combination of copper and zinc in brass creates a versatile and durable material that is commonly used in various applications, such as plumbing fixtures, musical instruments, and decorative items.
32.
Which of the following statements about food chains and energy flow through ecosystems is FALSE?
Correct Answer
B. Detritivores feed at all trophic levels except the producer level.
Explanation
Detritivores are organisms that feed on dead organic matter, such as decaying plants and animals. They play an important role in the ecosystem by breaking down and recycling nutrients. However, detritivores do not feed at all trophic levels except the producer level. They primarily feed at the decomposer level, which is the final trophic level in a food chain or web. Therefore, the statement that detritivores feed at all trophic levels except the producer level is false.
33.
When a doctor gives you an antibiotic when you are sick, he/she always tells you to keep taking the
antibiotic until it is all finished. The reason he/she tells you this is because:
Correct Answer
C. Allowing the more antibiotic-tolerant bacteria to survive may encourage a population of antibiotic-resistant bacteria to evolve.
Explanation
When a doctor gives you an antibiotic, they always tell you to finish the entire course because allowing the more antibiotic-tolerant bacteria to survive may encourage a population of antibiotic-resistant bacteria to evolve. This means that if you stop taking the antibiotic before completing the course, some bacteria may survive and develop resistance to the antibiotic. These antibiotic-resistant bacteria can then multiply and spread, making it harder to treat infections in the future. Therefore, it is important to finish the entire course of antibiotics to ensure that all bacteria are eliminated and reduce the risk of antibiotic resistance.
34.
Under a light microscope, tiny dots can be seen in the cytoplasm of living plant and animal cells.
These are likely to be:
Correct Answer
B. Ribosomes
Explanation
Under a light microscope, tiny dots seen in the cytoplasm of living plant and animal cells are likely to be ribosomes. Ribosomes are small, spherical organelles involved in protein synthesis. They can be found in the cytoplasm of cells and are responsible for translating genetic information from DNA into proteins.
35.
An organism has the genotype AaBbCCDd. How many possible combinations of alleles do the gametes of this organism produce?
Correct Answer
D. 8
Explanation
The organism has four different gene loci, each with two possible alleles. The number of possible combinations of alleles in the gametes can be calculated by multiplying the number of possible alleles at each locus. Therefore, 2 x 2 x 2 x 2 = 8 possible combinations of alleles can be produced by the gametes of this organism.
36.
-
Brown eyes are dominant over blue eyes. Which cross would produce a blue-eyed child?
-
BB x bb
-
Bb x Bb
-
BB x Bb
-
BB X BB
Correct Answer
B. Bb x Bb
Explanation
The correct answer is Bb x Bb. In this cross, both parents have one dominant allele (B) and one recessive allele (b) for eye color. When they reproduce, there is a 25% chance of the child inheriting two recessive alleles (bb) and having blue eyes.
37.
The more active the cell/tissue such as muscle, the greater the number of__________
Correct Answer
B. Mitochondria
Explanation
The more active a cell or tissue, such as muscle, the greater the number of mitochondria. Mitochondria are the powerhouses of the cell, responsible for producing energy in the form of ATP through cellular respiration. Active cells require more energy to carry out their functions, and therefore, they need more mitochondria to meet their energy demands. This is why the number of mitochondria increases in cells or tissues that are highly active.
38.
What do you call the type of cell division exhibited by sex cells wherein the chromosome number of the four daughter cell is reduces to half the somatic number?
Correct Answer
B. Meiosis
Explanation
Meiosis is the correct answer because it is the type of cell division exhibited by sex cells, also known as gametes. In meiosis, the chromosome number of the four daughter cells is reduced to half the somatic number, allowing for genetic variation and the production of haploid cells. Mitosis, on the other hand, is the type of cell division that produces two identical daughter cells with the same chromosome number as the parent cell. Fission and budding are different forms of asexual reproduction and not related to the reduction of chromosome number.
39.
Mutation is caused by all of the following except:
Correct Answer
C. Surgery
Explanation
Mutation refers to a change in the DNA sequence of an organism. It can be caused by various factors such as chemicals, viruses, and radiation. However, surgery is not a known cause of mutation. Surgery involves physical manipulation of tissues or organs, but it does not directly affect the DNA sequence. Therefore, surgery is not a cause of mutation.
40.
What type of reproduction involves gametes?
Correct Answer
B. Sexual
Explanation
Sexual reproduction involves the production of gametes (sperm and egg cells) which fuse together during fertilization to form a new individual. This type of reproduction allows for genetic variation and diversity in offspring, as the genetic material from two parents is combined. In contrast, asexual reproduction does not involve the production of gametes and offspring are genetically identical to the parent. Fission is a type of asexual reproduction where an organism splits into two or more parts, while fusion refers to the merging of two or more gametes during sexual reproduction.
41.
Viruses are not considered free-living because
Correct Answer
D. They cannot reproduce outside a living cell
Explanation
Viruses are not considered free-living because they cannot reproduce outside a living cell. Unlike other organisms, viruses lack the necessary cellular machinery to carry out essential metabolic processes and reproduce on their own. They rely on infecting a host cell, taking over its machinery, and using it to replicate their genetic material and produce new virus particles. Without a living cell to infect and replicate in, viruses are unable to survive or reproduce, making them dependent on a host organism for their survival.
42.
The conversion of radiant energy in most plants are called
Correct Answer
B. Photosynthesis
Explanation
Photosynthesis is the correct answer because it is the process by which plants convert radiant energy from the sun into chemical energy. This process occurs in the chloroplasts of plant cells, where sunlight is absorbed by chlorophyll and used to convert carbon dioxide and water into glucose and oxygen. Photosynthesis is essential for the growth and survival of plants, as it provides them with the energy they need to carry out their metabolic processes. Fermentation, respiration, and transpiration are not processes involved in the conversion of radiant energy in plants.
43.
It is the change in form or structure in an organ or organism during growth
Correct Answer
D. Metamorphosis
Explanation
Metamorphosis refers to the change in form or structure of an organ or organism during growth. It involves a complete transformation, often accompanied by distinct stages, such as the caterpillar turning into a butterfly. Mitosis and meiosis are processes of cell division, while mutation refers to a change in DNA sequence. The given answer, metamorphosis, is the most appropriate choice as it specifically relates to the described change in form or structure during growth.
44.
Oxygen laden blood pumped by the heart is supplied to different parts of the body through the channels called
Correct Answer
C. Aorta
Explanation
The correct answer is aorta. The aorta is the main artery in the body that carries oxygenated blood from the heart to all the different parts of the body. It is responsible for supplying oxygen and nutrients to the organs, tissues, and cells. The other options, such as artery, ventricles, and veins, are not the main channels through which oxygenated blood is supplied to the body.
45.
It is the totality of an individual’s physical, intellectual, emotional and social characteristics
Correct Answer
B. Personality
Explanation
Personality refers to the combination of an individual's physical, intellectual, emotional, and social characteristics. It encompasses all aspects of a person's behavior, thoughts, and feelings, and is unique to each individual. Personality is shaped by various factors, including genetics, environment, and personal experiences. It influences how individuals interact with others and navigate the world around them. Therefore, personality is the best fit for the given description.
46.
The transport system of the human body is the
Correct Answer
C. Circulatory system
Explanation
The circulatory system is responsible for transporting oxygen, nutrients, hormones, and other essential substances throughout the body. It consists of the heart, blood vessels, and blood. The digestive system is responsible for breaking down food and absorbing nutrients, while the respiratory system is responsible for the exchange of oxygen and carbon dioxide. The endocrine system is responsible for producing and regulating hormones. However, the circulatory system is specifically designed to transport these substances to all parts of the body, making it the correct answer.
47.
They are bacteria that feed on dead materials.
Correct Answer
D. Saprophytes
Explanation
The term for bacteria that feed on dead materials is "saprophytes." Saprophytic bacteria are decomposers that play a vital role in breaking down organic matter, such as dead plants and animals, into simpler substances, thereby recycling nutrients back into the ecosystem. They are not typically considered harmful bacteria or germs. "Scavengers" is a more general term that can refer to various organisms, including animals, that feed on dead or decaying matter.
48.
Some organisms living in a garden included dragonflies, bugs, roses, grasshoppers, grasses, worms and spiders. Collectively, these organisms represent a
Correct Answer
B. Community
Explanation
The organisms listed in the question are all living in the same garden, indicating that they are interacting with each other and sharing the same resources. This suggests that they form a community, which refers to a group of different species living in the same area and interacting with each other. A biome refers to a large geographical area with similar climate and vegetation, so it is not the correct answer. Habitat refers to the specific environment where an organism lives, and population refers to a group of individuals of the same species living in the same area, both of which are more specific than the given scenario.
49.
DNA is to genes as chromatin is to
Correct Answer
D. Chromosome
Explanation
DNA is the genetic material that carries the instructions for making proteins and other molecules in the cell. Genes are specific segments of DNA that contain the instructions for making a particular protein. Similarly, chromatin refers to the DNA and proteins that make up the chromosomes. Chromosomes are structures that contain the DNA and genes, and they play a crucial role in the organization and transmission of genetic information during cell division. Therefore, the analogy suggests that chromatin is the material that makes up chromosomes, just as DNA is the material that makes up genes.
50.
The totality of pattern of relationship between living organisms and their environment is the basic concern of
Correct Answer
D. Ecology
Explanation
Ecology is the study of the relationships between living organisms and their environment. It focuses on understanding the interactions, adaptations, and dependencies between different species and their surroundings. Physiology is the study of the functions and processes of living organisms, botany is the study of plants, and biology is the study of living organisms in general. However, ecology specifically looks at the overall patterns and dynamics of how organisms interact with each other and their environment, making it the correct answer in this context.