A General Highschool Science Knowledge Quiz

Explanation
Conservation refers to the careful and responsible use of natural resources by humans. It involves the sustainable management and preservation of these resources to ensure their availability for future generations. Conservation aims to prevent depletion, degradation, or wasteful use of natural resources, such as water, forests, wildlife, and minerals. It involves strategies like reducing consumption, promoting renewable energy, protecting biodiversity, and implementing sustainable practices. Conservation is crucial for maintaining ecological balance, preserving biodiversity, mitigating climate change, and promoting the long-term well-being of both the environment and human society.

Explanation
A snail is an invertebrate because it does not have a backbone or a spinal column. Invertebrates make up the majority of animal species and include organisms such as insects, worms, and mollusks like snails. They rely on exoskeletons or other structural adaptations for support and protection. Fish, frog, and lizard are all vertebrates because they possess a backbone or a spinal column.

Explanation
Lizards possess homodont teeth, which means that all their teeth are the same in shape and size. This allows them to grip and swallow their prey whole, without the need for chewing. Unlike lizards, rabbits, monkeys, and pipes have heterodont teeth, which are different in shape and size and serve different functions, such as tearing, grinding, and cutting.

Explanation
Photosynthesis is the correct answer because it is the process by which plants produce carbohydrates. During photosynthesis, plants use sunlight, water, and carbon dioxide to produce glucose and oxygen. This process occurs in the chloroplasts of plant cells and is essential for the survival and growth of plants. Phosphorylation is the process of adding a phosphate group to a molecule, while photolysis refers to the breakdown of molecules by light. Reproduction is the process by which organisms produce offspring.

Explanation
Enamel is the hardest part of the human teeth. It is the outermost layer that covers the crown of the tooth. Enamel is composed of minerals, mainly hydroxyapatite, which makes it extremely strong and durable. It protects the underlying dentine and pulp from damage caused by chewing, biting, and other external forces. Enamel also provides a smooth surface for easy cleaning and helps maintain the shape and structure of the tooth.

Explanation
When the temperature of a gas increases, its volume also increases, assuming constant pressure. This relationship is described by Charles's Law. According to Charles's Law, the volume of a gas is directly proportional to its temperature in Kelvin.

To solve this problem, we need to convert the temperatures from Celsius to Kelvin. -20°C is equivalent to 253.15 K and 0°C is equivalent to 273.15 K.

We can set up a proportion to find the new volume:
(Volume1 / Temperature1) = (Volume2 / Temperature2)

Plugging in the given values, we get:
(506 cm3 / 253.15 K) = (Volume2 / 273.15 K)

Simplifying the equation, we find:
Volume2 = (506 cm3 * 273.15 K) / 253.15 K
Volume2 = 545.95 cm3

Rounding to the nearest whole number, the new volume when the temperature is raised to 0°C is 546 cm3.

Explanation
At the point of melting, solid and liquid exist at equilibrium. Melting is the process in which a solid substance changes into a liquid state when heated. At this point, the temperature is at the melting point, and the solid substance starts to break down and transition into a liquid. The molecules gain enough energy to overcome the forces holding them together in a solid structure, resulting in the coexistence of solid and liquid phases.

Explanation
Silicate glass is called a supercooled liquid because it is an amorphous solid that lacks a crystalline structure. It has a disordered arrangement of atoms, similar to that of a liquid, even though it appears solid. Silicate glass is formed by rapidly cooling molten silicates, preventing the atoms from arranging themselves into a crystalline structure. This results in a material that has properties of both a liquid and a solid, making it a supercooled liquid.

Explanation
The electronic configuration of element X is 1s2 2s2 2p4, which means it has 6 valence electrons. The electronic configuration of element Y is 1s2 2s2 2p6 3s2, which means it has 8 valence electrons. To achieve a stable electron configuration, element X needs to gain 2 electrons, while element Y needs to lose 2 electrons. Therefore, the compound formed will have 2 atoms of Y and 3 atoms of X, resulting in the formula Y2X3.

Explanation
CO2 is a linear molecule because it consists of two oxygen atoms bonded to a central carbon atom. The carbon-oxygen double bonds are arranged in a straight line, resulting in a linear shape. The other molecules listed are not linear. BCl3 has a trigonal planar shape, NH3 has a pyramidal shape, and H2O has a bent shape due to the presence of lone pairs of electrons.

Explanation
The ruler balances when the object is placed at the 15cm mark. This means that the moment on one side of the ruler (due to the object) is equal to the moment on the other side (due to the weight of the ruler). The moment is calculated by multiplying the force by the distance from the pivot point. Since the object has a mass of 10N and is placed 5cm from the pivot point, the moment on one side is 10N * 5cm = 50 Ncm. The ruler balances when the weight of the ruler creates a moment of 50 Ncm as well. Since the distance from the pivot point to the center of mass of the ruler is 15cm, the weight of the ruler must be 50 Ncm / 15cm = 10 N.

Explanation
The image formed on the retina is real because it can be projected onto a screen. It is also inverted because the light rays cross over each other at the lens, causing the image to be flipped upside down compared to the object being viewed.

Explanation
The work done on an object is calculated by multiplying the force applied to the object by the distance over which the force is applied. In this case, the force applied is equal to the weight of the bag of grains, which can be calculated as mass multiplied by the acceleration due to gravity (F = m*g). The distance over which the force is applied is the height the bag is raised, which is 1.2m. Therefore, the work done on the load is equal to the force applied multiplied by the distance, which is (75kg * 10ms^-2) * 1.2m = 900 J.

Explanation
To convert a temperature reading from Celsius to Kelvin, you need to add 273.15 to the Celsius value. In this case, adding 273.15 to 5oC gives us 278.15 K. However, Kelvin values are usually rounded to the nearest whole number, so the correct answer is 278 K.

Explanation
Water wets glass due to adhesion, which is the attractive force between molecules of different substances. In this case, the water molecules are attracted to the glass molecules, causing them to spread out and wet the surface of the glass. Adhesion allows water to form a thin film on the glass, rather than beading up or sliding off. This property is important in many applications, such as the ability of water to stick to the sides of a glass and be used as a cleaning agent.

Explanation
Two dozens is equal to 24. A gross is equal to 144. To find the percentage, we divide 24 by 144 and multiply by 100. This gives us 16.6666...%. Rounding this to the nearest whole number, the correct answer is 17.0%.

Explanation
The mean deviation is a measure of the average distance between each data point and the mean of the data set. To find the mean deviation, we first find the mean of the given data set, which is (10+6+8+2+4)/5 = 6. Then, we calculate the absolute difference between each data point and the mean: |10-6| = 4, |6-6| = 0, |8-6| = 2, |2-6| = 4, |4-6| = 2. The sum of these absolute differences is 4+0+2+4+2 = 12. Finally, we divide this sum by the number of data points, which is 5, to get the mean deviation: 12/5 = 2.4.

Explanation
The length of a line segment can be found using the distance formula, which is derived from the Pythagorean theorem. In this case, the x-coordinates of P and Q are the same, so the horizontal distance between them is 7 - 3 = 4. The y-coordinates are also the same, so the vertical distance is 1 - 1 = 0. Since the vertical distance is 0, it does not contribute to the length of the line segment. Therefore, the length of the line segment PQ is equal to the horizontal distance, which is 4.

Explanation
The equation of a straight line can be determined using the point-slope form, which is y - y1 = m(x - x1), where m is the gradient and (x1, y1) is a point on the line. In this case, the gradient is 3/2 and the point is (4, -1). Plugging these values into the point-slope form, we get y - (-1) = (3/2)(x - 4), which simplifies to 2y - 3x = -14. Therefore, the correct answer is 2y - 3x = -14.

Explanation
The correct answer is {4, 6, 8, 10, 12, 14, 16}. This is because P' represents the complement of P, which includes all the elements in the universal set U that are not in P. Q represents the set of even numbers between 1 and 18. The intersection (n) of P' and Q includes all the elements that are common to both sets. In this case, the common elements are {4, 6, 8, 10, 12, 14, 16}, which are all the even numbers between 1 and 18 that are not prime.