Question 1

Salifa carried out an investigation to find out the preferred environment of an organism G. Twenty organisms G were put in the middle of Dish A. After 15 minutes, the number of organism G in each section of Dish A was counted. She repeated the investigation with Dish B and Dish C while using the same number of organism G in each dish. Which of the following shows the likely number of organism G in each section of Dish B and C?

Accepted Answer

C. Dish B: damp 6, dry 14; Dish C: dark 12, light 8. In Dish A the sections show damp-and-dark=4, dry-and-dark=9, damp-and-light=1, dry-and-light=6. Adding: damp total = 4+1 = 5, dry total = 9+6 = 15, so organism G prefers dry over damp. Dark total = 4+9 = 13, light total = 1+6 = 7, so organism G prefers dark over light. For Dish B (damp vs dry) the count should favour dry: 6 damp, 14 dry. For Dish C (dark vs light) the count should favour dark: 12 dark, 8 light. Option C matches both preferences.

Question 2

Peter counted the plants and animals in his aquarium. The results are shown below. Which of the following statement(s) about the plants and animals in the aquarium is/are definitely correct? A There is one aquarium community. B There are more types of animals than plants. C The population size of all the animals is greater than that of all the plants.

Accepted Answer

B. A and C only. The bar chart shows plants = 15 and animals = 30 (number of organisms). Statement A is correct: all the plants and animals living together in the aquarium form one community. Statement C is correct: the population (number) of animals (30) is greater than that of plants (15). Statement B is wrong: the graph shows the NUMBER of organisms, not the number of different TYPES, so we cannot conclude there are more types of animals than plants. Hence A and C only.

Question 3

Which of the following is a reason for the young of some animals to be travelling in groups with their parents?

Accepted Answer

A. Parents may protect their young from danger.. Young animals travel in groups with their parents mainly so the parents can protect them from predators and other dangers, increasing the young's chance of survival. Options B, C and D describe roles the young cannot reliably perform and are not the reason for grouping.

Question 4

A food web consists of five organisms, A, B, C, D and E. The table below shows some information about the organisms. Food producer: D; Prey only: B; Both predator and prey: C, E; Predator only: A. Which one of the following shows a possible food relationship among the five organisms?

Accepted Answer

D. Food web option 4. The correct web must have D as producer (arrows only leaving D, none entering), B as prey only (arrows only leaving B, none entering), A as predator only (arrows only entering A, none leaving), and C and E as both predator and prey (arrows in and out). Option 4 shows D as the producer feeding into B and C, B feeding into E, C being eaten, and A only receiving arrows (predator only), satisfying every role.

Question 5

The diagram below shows organisms in a food chain: plant → insect → bird. Which of the following statements are true about the food chain? A The insect obtains its food from the plant only. B The source of energy for the food chain is the sun. C Not all the energy from the plant could be transferred to the bird. D The bird does not depend on the plant for food directly or indirectly.

Accepted Answer

C. A, B and C only. A is true: in this food chain the insect eats only the plant. B is true: the Sun is the ultimate energy source for all food chains. C is true: energy is lost at each level (e.g. as heat), so not all the plant's energy reaches the bird. D is false: the bird depends on the plant indirectly (plant → insect → bird). Therefore A, B and C only.

Question 6

Study the diagram below. [A cow is shown giving out animal waste and giving out carbon dioxide and water vapour.] The substances produced by the cow undergo a process to release other substances that are returned to the soil. Which of the following correctly matches the process with the substance(s) that are returned to the soil for plants to absorb for growth?

Accepted Answer

D. Decomposition — mineral salts. Animal waste is broken down by decomposers (bacteria and fungi) through the process of decomposition. Decomposition returns mineral salts (nutrients) to the soil, which plants absorb through their roots for growth. Respiration and evaporation do not return nutrients to the soil.

Question 7

The diagram below shows a fish in its habitat. Which of the following characteristics help the fish to swim fast and hide from its predator?

Accepted Answer

D. swim fast: streamlined body; hide from predator: stripes on its body. A streamlined body reduces water resistance, allowing the fish to swim fast. Stripes on its body act as camouflage among the plants/reeds in its habitat, helping it hide from predators. The other options pair characteristics that do not correctly serve both functions.

Question 8

Three pupils made the following statements about adaptation of organisms. Lenny: An organism must have adaptations for it to survive the physical conditions of its habitat. Manju: Only plants develop adaptations for conserving water. Neela: Both the young and adult of mammals show behavioural adaptations for reproduction. Which pupil(s) had made the correct statement about adaptation?

Accepted Answer

B. Lenny only. Lenny is correct: organisms must be adapted to survive the physical conditions of their habitat. Manju is wrong: animals (e.g. desert animals) also have adaptations for conserving water, not only plants. Neela is wrong: reproduction is not shown by the young of mammals, only by adults that are sexually mature. So only Lenny is correct.

Question 9

The diagrams below show two different plant adaptations: a twining stem and needle-like leaves. Which of the following correctly matches the adaptations of each plant to its purpose?

Accepted Answer

C. twining stem: to obtain more light; needle-like leaves: to reduce water loss. A twining stem allows a climbing plant to wind around a support and grow upward toward sunlight, so it can obtain more light for photosynthesis. Needle-like leaves have a small surface area, which reduces water loss through transpiration (an adaptation for dry conditions). Option C matches both correctly.

Question 10

The diagram below shows a wind-pollinated flower [labelled dull-coloured petal, stigma, anther, ovary]. What adaptation does the flower have for wind pollination?

Accepted Answer

A. Feathery stigma. A feathery stigma has a large surface area that sticks out of the flower to catch pollen grains carried by the wind, which is a key adaptation for wind pollination. Dull-coloured petals only mean the flower does not attract insects; they are not the feature that actively enables wind pollination in the way a feathery stigma does.

Question 11

Acid rain is harmful to our environment. Which one of the following is most likely to cause more acid rain?

Accepted Answer

A. more pollutants in the air. Acid rain is caused by pollutant gases (such as sulfur dioxide and nitrogen oxides) released into the air, which dissolve in rainwater to form acids. Therefore more pollutants in the air will most likely cause more acid rain.

Question 12

Which one of the following actions indirectly contributes to flooding due to rising sea level?

Accepted Answer

C. more people driving instead of taking public transport. More people driving releases more carbon dioxide, a greenhouse gas that causes global warming. Global warming melts polar ice and causes sea water to expand, raising sea levels and causing flooding. This is an indirect chain of effects, so option C is correct.

Question 13

Three plants, Q, R and S, were planted as shown in Figure 1 in 2010. Figure 2 shows the locations of the plants in 2014. Which of the following is the most likely method of dispersal for the fruits of plants Q, R and S?

Accepted Answer

D. Q: by explosive action; R: by water; S: by wind. In Figure 2, plant Q has spread its offspring in a tight cluster close to the parent — typical of explosive/splitting dispersal. Plant R's offspring have spread along and down the river's flow, indicating water dispersal. Plant S's offspring are scattered widely and further away, indicating wind dispersal. Option D matches Q = explosive, R = water, S = wind.

Question 14

Study the diagram below. Pollen grains → (Process J) → Female flower → (Process K) → Ovary becomes M and Ovules become N. Which of the following correctly identifies J, K, M and N?

Accepted Answer

C. J: pollination; K: fertilisation; M: fruit; N: seed. Pollen grains landing on the female flower is pollination, so Process J = pollination. This is followed by fertilisation, so Process K = fertilisation. After fertilisation the ovary develops into the fruit (M = fruit) and the ovules develop into seeds (N = seed). Option C is correct.

Question 15

Which of the following statement(s) about human reproduction is/are true? A The ovaries produce eggs. B The sperms are produced in the penis. C Only one sperm is needed to fertilise an egg. D The ovaries usually release many eggs at a time.

Accepted Answer

B. A and C only. A is true: the ovaries produce eggs. C is true: only one sperm is needed to fertilise one egg. B is false: sperms are produced in the testes, not the penis. D is false: the ovaries usually release only one egg at a time. Therefore A and C only.

Question 16

The diagram below shows a simple representation of the human circulatory system. Arrows E, F, G and H represent the flow of blood to different parts of the body [lungs, heart, other parts of the body]. Which one of the following graphs correctly represents the amount of oxygen in E, F, G and H?

Accepted Answer

B. Graph 2. E = heart to lungs (deoxygenated, low oxygen). F = body to heart (deoxygenated, low but slightly different). G = lungs to heart (freshly oxygenated, highest oxygen). H = heart to body (oxygenated, high but slightly less than G after none is lost yet — still high). The correct pattern is E lowest, G highest, with F and H in between; the graph in option (2) shows E lowest, rising to G highest, matching the oxygen levels correctly.

Question 17

The diagram below represents the composition of gases in the air inhaled by a human [Q: carbon dioxide, other gases and water vapour; R: nitrogen; S: oxygen]. Which of the following statements are false about the composition of gases in the exhaled air of a human? A Amount of Q increases. B Amount of S increases. C Amount of R remains the same. D Amount of Q, R and S decrease.

Accepted Answer

B. B and D only. The question asks which statements are FALSE. In exhaled air: Q (carbon dioxide/water vapour) increases — so A is true. S (oxygen) decreases — so statement B ('S increases') is false. R (nitrogen) remains the same — so C is true. Since Q increases and R stays the same, statement D ('Q, R and S decrease') is false. The false statements are B and D.

Question 18

Which of the following statements is true about the human digestion system? A Absorption of water takes place in the small intestine. B Absorption of digested food takes place in the small intestine. C The start of the digestion process takes place in the stomach. D Chewing food into smaller pieces can speed up the rate of digestion.

Accepted Answer

C. B and D only. B is true: absorption of digested food takes place in the small intestine. D is true: chewing breaks food into smaller pieces, increasing surface area and speeding up digestion. A is false: absorption of water takes place mainly in the large intestine. C is false: digestion starts in the mouth, not the stomach. Therefore B and D only.

Question 19

The diagram below shows a hydroelectric power station [water (A) held high behind a dam, turbine (B), power lines (C)]. The water turns the turbine such that the generator can produce electricity. Which of the following identifies the main forms of energy at points A, B and C?

Accepted Answer

B. A: gravitational potential energy; B: kinetic energy; C: electrical energy. Water A is stored high up behind the dam, so it has gravitational potential energy. As it falls and turns the turbine B, the turbine has kinetic energy (energy of movement). The generator converts this to electrical energy carried by the power lines C. Option B matches: A = gravitational potential, B = kinetic, C = electrical.

Question 20

Study the graph below [showing gravitational potential energy increasing over time while kinetic energy decreases over time]. Which of the following actions would show the same energy conversions as the graph above?

Accepted Answer

B. Kicking a ball upwards.. The graph shows kinetic energy decreasing and gravitational potential energy increasing over time — i.e. kinetic energy is being converted into gravitational potential energy. This happens when an object moves upward and slows down. Kicking a ball upwards: the ball starts fast (high kinetic energy) and rises while slowing (gaining gravitational potential energy), matching the graph. The others convert potential to kinetic (moving down).

Question 21

Hui Yin hung two objects X and Y on two identical springs as shown below [Spring A holding object X, Spring B holding object Y; Spring B is stretched longer]. Which one of the following statements correctly explains why Spring B is longer than Spring A after the objects are hung on them?

Accepted Answer

A. The mass of object Y is more than that of object X.. The two springs are identical, so a longer stretch in Spring B means a greater downward force pulling on it. This means object Y has more weight, i.e. a greater mass than object X. Option A correctly explains this. (Option D is also about gravitational force, but the direct cause the question tests is that Y has more mass; the mark scheme gives answer 1.)

Question 22

The diagram below shows a toy train on a flat surface. The direction of the toy train's movement depends on the amount of forces K and M [Force K pushes right toward Y, Force M pushes left toward X]. Which of the following are the correct reasons for the train's possible movements? A The train moves towards X — Force K is greater than Force M. B The train moves towards Y — Force M is smaller than Force K. C The train does not move — Force M is equal to Force K.

Accepted Answer

C. B and C only. Force K points toward Y (right) and Force M points toward X (left). B is correct: if Force M is smaller than Force K, the net force is toward Y, so the train moves toward Y. C is correct: if the forces are equal they balance and the train does not move. A is wrong: if Force K is greater than Force M, the train would move toward Y, not X. So B and C only.

Question 23

The diagram below shows an electrical circuit that consists of four objects, J, K, L and M, that are made of different materials. It was observed that the bulb lit up. Which of the following correctly shows the materials that the objects could be made of?

Accepted Answer

C. J: aluminium; K: iron; L: wood; M: copper. For the bulb to light, there must be a complete circuit of conductors. In this circuit J, K and M are in the main loop that must all conduct, while L is on a parallel branch. Option C makes J = aluminium (conductor), K = iron (conductor), M = copper (conductor) — a complete conducting path — while L = wood (non-conductor) simply does not carry current on its branch. All the objects needed to complete the loop conduct, so the bulb lights.

Question 24

Rui Xing wants to test how the number of bulbs arranged in series affects the brightness of each bulb. He sets up an electric circuit using a bulb, some batteries and an object X made of a certain material as shown below. In order to ensure a fair test, which of the following variables must he keep constant? A Number of bulbs B Brightness of bulbs C Number of batteries D Type of material for X

Accepted Answer

B. C and D only. The variable being changed (independent) is the number of bulbs, so A cannot be kept constant. The variable being measured (dependent) is the brightness of the bulbs, so B is not something he controls. To make it a fair test he must keep constant the other variables: the number of batteries (C) and the type of material for X (D). Therefore C and D only.

Question 25

Rajan created a circuit card as shown below. He then used the circuit tester to test out his circuit card. Which of the following pairs of points would allow the bulb to light up? A Points E and K B Points G and M C Points J and M D Points H and J

Accepted Answer

D. B, C and D only. The bulb lights only when the two tested points are connected by a conducting wire on the card. The card has wires connecting E–G–H along the top, J–M along the bottom, and a diagonal wire from G to M. Following the connections, points that are joined by wire include G and M (via the diagonal), J and M (bottom wire), and H and J (H connects along top to G, then diagonal to M, then to J) — so B, C and D allow the bulb to light. Points E and K are not connected, so A does not. Therefore B, C and D only.

Question 26

The letters, A, B, C and D, represent four students standing at different positions of a corridor [with an angled mirror at the corner]. Without moving from their current positions, which pair of students will be able to see each other in the mirror?

Accepted Answer

C. B and D. Light travels in straight lines and reflects off the mirror following the law of reflection (angle of incidence = angle of reflection). Based on the positions in the L-shaped corridor and the angled mirror at the corner, the light path from B reflects off the mirror to reach D, so students B and D can see each other in the mirror. The other pairs do not have a valid reflected line of sight.

Question 27

Aini carried out an experiment to find out the effect of the Sun's heat on different materials. She used 4 identical empty cans made of different materials, A, B, C and D, for the set-ups shown below. These set-ups were placed under direct sunlight. She recorded the temperature of air in the cans over time. Based on her results, which of the materials is most suitable for making a lunch box to keep food warm for the longest time?

Accepted Answer

C. C. A good lunch box should be a poor conductor of heat, so it gains (and loses) heat the slowest, keeping food warm longest. From the table, material C's air temperature rose the least over 15 minutes (28 → 31.5 → 33 → 34.5 °C, a rise of only 6.5 °C), the smallest change of all four materials. This means C is the poorest heat conductor and is most suitable for keeping food warm the longest.

Question 28

Lucy filled two identical containers with the same amount of water. She then added different objects, X and Y, into each container and observed the final water level in each container as shown below [Beaker A with object X, higher water level; Beaker B with object Y, lower water level]. Based on her results, what can Lucy conclude? A Objects X and Y have different masses. B Objects X and Y have different volumes. C Object X absorbs more water than object Y.

Accepted Answer

A. B only. The water rises higher in Beaker A than in Beaker B, meaning object X pushed aside (displaced) more water than object Y. This shows the two objects have different volumes (B is correct). The experiment tells us nothing about their masses (A cannot be concluded) or whether either object absorbs water (C cannot be concluded). Therefore B only.

Question 29

Zec placed an iron nail near a steel rod and a copper rod as shown in the set-up below [an electromagnet circuit: batteries, iron nail wound with wire, a switch and a bulb; a copper rod and a steel rod hang nearby on strings]. Which of the following will Zec most likely observe when he closes the switch? A The bulb lights up. B The steel rod moves towards the iron nail. C The copper rod remains at the same position. D Both the steel rod and copper rod will move towards the iron nail.

Accepted Answer

B. B and C only. Wait — the mark scheme gives answer 2 (B and C only). When the switch closes, current flows and the iron nail becomes an electromagnet. A magnet attracts magnetic materials: the steel rod is magnetic, so it moves towards the iron nail (B is correct). Copper is non-magnetic, so the copper rod stays in place (C is correct). Statement D is wrong because copper does not move; statement A about the bulb is not part of the correct pair. Therefore B and C only.

Question 30

Shannon placed 2 similar iron cubes on 2 different surfaces as shown in the diagram below. The 2 magnets used were of the same strength. [Set-up X: magnet and iron cube 10 cm apart on a glass surface; Set-up Y: magnet and iron cube 10 cm apart on a carpeted surface.] The table below shows the time taken for the iron cubes to come into contact with the magnets. Based on her findings in the table above, which one of the following best explains her observations?

Accepted Answer

D. There was less friction between the iron cubes and the surfaces in set-up X than set-up Y.. The iron cube in set-up X reached the magnet faster (3, 3, 2 s) than in set-up Y (4, 5, 4 s), even though the magnets were of equal strength and the distances equal. The glass surface (X) is smoother than the carpeted surface (Y), so there was less friction between the iron cube and the surface in set-up X, allowing it to move to the magnet faster. Option D is the best explanation.

P6 Science SA2 2014 — Nanyang

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P6 Science SA2 2014 — Nanyang

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