Question 1

Which of the following energy pyramids correctly shows a balance in the food chain below?

A → B → C → D

Accepted Answer

B. Pyramid with D at top, then C, then B, then A at the base. In a balanced energy pyramid the producer (first organism in the food chain, A) is the most numerous and forms the wide base, while energy decreases up the chain (B, C, then D as the top predator at the apex). Only the pyramid with A at the base and D at the top correctly reflects the chain A→B→C→D.

Question 2

Kumar conducted two experiments on food relationships in a community consisting of a plant and three other organisms, A, B and C. The table below shows the observations at the end of the experiments after three days.

Based on the experiments above, which of the following shows a possible food relationship amongst the plant and the organisms, A, B and C?

Accepted Answer

A. Plant → A, A → C, C → B. In Experiment 1, leaves were reduced to bits and organism C survived, so C eats the plant (Plant→C). Organism A disappeared, so something ate A. In Experiment 2, only B survived, so B ate the others; A and C disappeared. This shows Plant→A→C and C→B style relations, i.e. the plant is eaten, A is eaten by C, and C is eaten by B. Option (1) shows Plant→A, A→C and C→B, the only consistent web.

Question 3

The food web below shows the food relationships between organisms, A, B, C, D, E, F, G and H. Which of the following statements is true of the food web?

Accepted Answer

D. None of the organisms present in the food web is a plant-and-animal eater.. From the web, E is the producer. H is fed by both F and D (so A is false). The animals feeding directly on E are B, D, F and G — that is four plant-eaters, not three (so B is false). Not all organisms feed on E (so C is false). Checking each consumer, none eats both plants and animals, so D is correct.

Question 4

The diagram below shows the flow of energy between organisms, A, B, C and D, in an ecosystem. Which of the following correctly represents the role that organisms, A, B, C and D, play in the food web?

Accepted Answer

B. A Consumer, B Decomposer, C Producer, D Consumer. Energy flows A→B, C→B, D→A, C→D, D→B. C only gives out energy (to B and D) and receives none, so C is the producer. D receives from C and gives to A and B, so D is a consumer. A receives from D and gives to B, so A is a consumer. B receives energy from everything (A, C and D) and gives none out, so B is the decomposer. This matches option (2).

Question 5

The desert cottontail is a type of rabbit that lives in a desert. The two line graphs below show the relationship between the activity level of the desert cottontail and the temperature changes of the desert in a day. Which of the following conclusions can you make about the desert cottontail based on the graphs?

A: Its fur colour helps it to survive in a desert.
B: It is able to survive in a desert because it hibernates.
C: Its behavioural adaptation helps it to survive in the desert.
D: Its activity level increases when the temperature decreases.

Accepted Answer

D. C and D only. The graph shows activity level is high when temperature is low (night/early morning) and low when temperature is high (midday). So D is correct. Being active only when it is cool is a behavioural adaptation that helps it survive, so C is correct. The graph says nothing about fur colour (A) or hibernation (B). Hence C and D only.

Question 6

Tom saw Animal X in his room and he tried to catch it by its tail. However, its tail broke off and Animal X managed to escape. Which of the following shows the breaking of its tail help Animal X increase its chances of survival?

Accepted Answer

B. It helps Animal X to distract its predator.. Animal X is a gecko/lizard. When threatened, it sheds (drops) its tail; the detached tail wriggles and distracts the predator, giving the lizard time to escape. This increases its chance of survival.

Question 7

The diagrams below show the life cycles of two insects. Based on what you can observe from the life cycles above, which of the following best describes a similarity of the young of both insects?

Accepted Answer

B. They go through the pupal stage.. Both diagrams show four-stage (complete metamorphosis) life cycles: egg → larva → pupa → adult. Insect A (e.g. a fly/beetle) and Insect B (a mosquito) both pass through a pupal stage. The young (larvae) do not look like the parents, so the shared similarity is that both go through the pupal stage.

Question 8

The diagram below shows a seed growing into a young plant. Which of the following shows the direction in which food and water are being transported at Z?

Accepted Answer

A. food upwards, water upwards. Point Z is on the shoot (above the seed/soil), where the young shoot and leaves are growing. Water absorbed by the root is transported upwards to the leaves, and food stored in the seed is also transported upwards to the growing shoot tip. So at Z both food and water move upwards.

Question 9

A group of Primary 6 pupils counted the number of plants and animals in the school pond. They drew a bar chart based on their data collected as shown below. Which of the following statements about the plants and the animals in the pond is/ are correct?

A: There are 30 populations of animals.
B: There is at least 6 populations of plants and animals.
C: The number of floating plants and submerged plants are equal.

Accepted Answer

C. B and C only. The chart shows six bars (floating plants, partially submerged plants, submerged plants, no-legs animals, six-legs animals, more-than-six-legs animals), so there are at least 6 populations (B correct). Floating plants (10) and submerged plants (10) are equal (C correct). Statement A is wrong because the bars show the number of organisms, not 30 separate populations of animals. Hence B and C only.

Question 10

Jenny has a garden where she planted some vegetables and fruit trees. She always buries leftover food and bones in the garden instead of throwing them in dustbins. Why does Jenny bury these items?

Accepted Answer

D. They will decompose and provide nutrients for the plants.. When leftover food and bones are buried, decomposers (bacteria and fungi) in the soil break them down, releasing nutrients into the soil. These nutrients are absorbed by the plants for healthy growth, which is why Jenny buries them.

Question 11

Study the food web below. Which of the following statements are definitely true about the food web above?

A: There are three types of food producers in the web.
B: When the population of snakes decreases, the population of the crickets would increase.
C: The population of the deer is only affected by the population of the mountain lion.
D: When the populations of all the plants decrease, the populations of other organisms would decrease too.

Accepted Answer

A. A and D only. The producers are tree, shrubs and grass — three producers (A true). When all plants decrease, every organism that depends on them (directly or indirectly) decreases (D true). B is false because the snake does not eat crickets, so a fall in snakes would not increase crickets. C is false because the deer is also affected by its food source (the tree), not only the mountain lion. Hence A and D only.

Question 12

The diagram below shows three birds, X, Y and Z, which feed on fish. They are usually seen in different parts, D, E and F of the habitat below. Which of the birds, X, Y and Z, are most likely to be found at D, E and F?

Accepted Answer

C. D=Z, E=X, F=Y. Z is a tall, long-legged wading bird (stork), suited to standing on muddy ground (D). X is a duck with webbed feet for swimming in the deep pond (E). Y is a small kingfisher-type bird that perches in the tall tree (F) and dives for fish. So D=Z, E=X, F=Y, matching option (3).

Question 13

The picture below shows the fruit of the Rose of India. The fruits have seed pods which are hard and dry when matured and the seeds have wing-like structures. How does the Rose of India disperse its seeds?

A: By wind
B: By splitting
C: By animals

Accepted Answer

C. A and B only. The seed pods are hard and dry when mature — a feature of fruits that split open (explosive/splitting dispersal). The seeds have wing-like structures, which let them be carried by the wind. So the plant disperses its seeds both by splitting and by wind: A and B only.

Question 14

Which of the following diagrams below correctly shows the movement of blood in the human circulatory system?

Key: dashed line = blood rich in carbon dioxide; solid line = blood rich in oxygen.

Accepted Answer

B. Diagram 2. Blood rich in carbon dioxide (dashed) returns from the upper and lower body to the heart, is pumped to the lungs, releases carbon dioxide and is enriched with oxygen (solid) in the lungs, returns to the heart, and is then pumped out to the upper and lower body. Diagram (2) correctly shows carbon-dioxide-rich blood from the body to the heart then to the lungs, and oxygen-rich blood from the lungs to the heart then to the body.

Question 15

Shanti carried out an experiment with the following steps to show out how plants grow under certain conditions.
Step 1: She filled two identical flower pots with the same amount of garden soil.
Step 2: She labelled each pot, Pot A and Pot B, respectively.
Step 3: She planted the same number of the same type of seed in each pot.
Step 4: She placed Pot A in the garden and Pot B in a closed cupboard.
Step 5: She watered each pot with the same amount of water daily.

Which of the following was Shanti trying to show?

Accepted Answer

C. Sunlight is necessary for healthy plant growth.. All variables are kept the same (soil, seeds, water) except light: Pot A is in the garden (has sunlight) while Pot B is in a closed cupboard (no sunlight). The only changed variable is the presence of light, so the experiment tests whether sunlight is necessary for healthy plant growth.

Question 16

The picture below shows a solar panel on the roof of a house. The solar panel is connected to the water heater. Which of the following shows the energy conversion taking place in a solar-powered water heater?

Accepted Answer

A. light energy → electrical energy → heat energy. A solar panel converts light energy from the Sun into electrical energy. The electrical energy is then used by the water heater to produce heat energy to warm the water. So the conversion is light energy → electrical energy → heat energy.

Question 17

A marble was placed at the top of a curved slope as shown below. The graph below shows the changes in kinetic energy of the marble once it was released. Which of the following letters, E, F, G or H, in the graph represents the point where the marble was at the bottom of the slope?

Accepted Answer

B. F. At the bottom of the curved slope the marble moves fastest, so its kinetic energy is greatest — this corresponds to a peak of the kinetic-energy curve. Among the labelled points, F is at the top of a peak (maximum kinetic energy), so F marks where the marble is at the bottom of the slope. (G is at a trough = top of swing where KE is lowest.)

Question 18

The flowchart below is used to classify three different types of forces, A, B and C. Which of the following are the forces, A, B and C?

Accepted Answer

A. A Gravitational, B Magnetic, C Frictional. A: force acts from a distance (Yes) and is always a pull (Yes) → gravitational force. B: force acts from a distance (Yes) but is not always a pull (No, it can push or pull) → magnetic force. C: force cannot act from a distance (No) and always opposes the motion of an object (Yes) → frictional force. This matches option (1).

Question 19

Simone had four rods, P, Q, R and S, of unknown materials. She connected the rods in the circuit below. All the bulbs were connected correctly and were working properly. She observed that only Bulb T lit up when the circuit was closed. Which of the following correctly describes the electrical conductivity of the rods, P, Q, R and S?

Accepted Answer

D. P No, Q Yes, R No, S Unable to tell. Only Bulb T lit up. Bulb T is in the main loop with the battery and Q (in series with the part of the circuit through Q), so Q must conduct electricity (Yes). The bulbs in series with P and R did not light, so P and R do not conduct (No). S is on a branch where the bulb did not light but the path was incomplete for another reason, so its conductivity cannot be determined (Unable to tell). This matches option (4).

Question 20

The diagram below shows two shapes, P and Q, made of cardboard. Shape P is a triangle (5 cm base, 5 cm height) and Shape Q is a rectangle (10 cm tall, 5 cm wide). The two shapes are placed between a torch and a screen as shown below. Which of the following shows the shadow formed on the screen when the torch is switched on?

Accepted Answer

D. A rectangle with a downward-pointing triangle below it. Both shapes block light. Shape Q (rectangle) is nearer the screen and Shape P (downward-pointing triangle) is nearer the torch. Their shadows overlap and combine: the rectangle's shadow plus the triangle's shadow form a single shape that is a rectangle with a downward-pointing triangle extending from it. Both shapes are opaque so they cast a combined dark shadow, matching option (4).

Question 21

Caroline found four bars, W, X, Y and Z, made of different materials. She carried out a scratch test to investigate the hardness of the four bars. The table below shows the results of the test performed on the four bars. Based on the test results above, arrange the bars from the least hard to the hardest.

Accepted Answer

C. Y, Z, X, W. A harder material is scratched by fewer discs. W is scratched by no disc (hardest). X is scratched only by the iron disc. Z is scratched by iron and wooden discs. Y is scratched by all three discs (softest). From least hard to hardest: Y (3 scratches), Z (2), X (1), W (0) → Y, Z, X, W, matching option (3).

Question 22

The diagram below shows a ball rolling down a slope from point A and stopping at point D. Which of the following graphs shows the change in the amount of the gravitational potential energy and kinetic energy of the ball from point A to point D?

Key: solid line = Gravitational potential energy; dashed line = Kinetic energy.

Accepted Answer

A. Graph 1. As the ball rolls down from A to C, its height falls so gravitational potential energy decreases steadily to zero at C, while kinetic energy increases as it speeds up. From C to D the ball moves along the flat and slows down due to friction, so kinetic energy decreases back to zero at D while GPE stays at zero (height unchanged). Graph (1) shows GPE falling from A to C and KE rising then falling back to zero at D.

Question 23

Three similar bottles, W, X and Y, were filled to the brim with water. The bottles were tilted at the same angle but held at different heights above an empty metal box as shown below. Which of the following statements are true about the above experiment?

A: Water flowed out of the bottles, W, X and Y, at the same rate.
B: Water from the bottle, W, produced the loudest sound upon hitting the metal box.
C: Water from the bottles, W, X and Y, possessed the same amount of kinetic energy at height Z.
D: Water flowing out from the bottles, W, X and Y, possessed gravitational potential energy and kinetic energy when the bottles were tilted.

Accepted Answer

D. A, B and D only. The bottles are identical and tilted at the same angle, so water flows out at the same rate (A true). Bottle W is highest, so its water falls the greatest distance, gains the most kinetic energy and produces the loudest sound (B true). Flowing water has both height (GPE) and motion (KE) when the bottles are tilted (D true). C is false: at the same height Z the water from the three bottles is not moving at the same speed because each started falling from a different height, so their kinetic energies differ. Hence A, B and D only.

Question 24

Yvette conducted an experiment on Spring A and Spring B. She hung various loads one at a time on the springs and recorded the resulting length of the spring. Her results are shown in the graph below. Based on the graph, what can Yvette conclude about the springs?

A: The original length of Spring A is shorter than the original length of Spring B.
B: For the same load hung on the springs, Spring A extends more than Spring B.
C: Gravity acts on the mass hung on the springs but not on the springs.

Accepted Answer

B. A and B only. At zero load, Spring A's length (about 10 cm) is shorter than Spring B's (about 20 cm), so A is correct. As load increases, Spring A's line rises more steeply than Spring B's, so for the same load Spring A extends more, so B is correct. C is wrong because gravity acts on the springs as well as on the hung mass. Hence A and B only.

Question 25

A toy truck, at point X, was moving down a slope as shown below. After some time, the toy truck stopped at point Y. Compare the kinetic energy and the potential energy of the toy truck at point X and point Y. Which of the following is correct?

Accepted Answer

D. Kinetic energy at Y less, Potential energy at Y less. At X the truck is higher up the slope and moving, so it has potential energy and kinetic energy. At Y it is lower (so less gravitational potential energy) and it has stopped moving (so less/no kinetic energy). Therefore both kinetic energy and potential energy at Y are less than at X.

Question 26

Three bar magnets AB, CD and EF can be arranged as shown below. Which of the following arrangements of the magnets is possible?

Accepted Answer

A. Arrangement 1. In the reference arrangement the magnets line up A...B C...D E...F, so B and C attract (opposite poles) and D and E attract (opposite poles). This fixes the pole pattern. Testing each option for whether touching ends have unlike (attracting) poles, only arrangement (1) keeps all touching ends as opposite poles, so it is a possible arrangement.

Question 27

Block G is released from the top of a smooth slope. It moves down and hits Block K at the bottom of the slope. After being hit by Block G, Block K slides along Surface L, before coming to a stop at the point T. Which of the following changes can increase the distance moved by Block K along Surface L?

Accepted Answer

B. increasing the height of the slope. Increasing the height of the slope gives Block G more gravitational potential energy, so it gains more kinetic energy and hits Block K harder, transferring more energy. Block K then moves a greater distance before friction stops it. Increasing the roughness (D) would increase friction and shorten the distance; width (A) and length of Surface L (C) do not increase K's energy.

Question 28

The diagram below shows the process of obtaining sea salt from sea water. This method of producing salt is still used till this day. Which of the following happens during the above method of producing salt?

Accepted Answer

C. Heat is gained by the seawater during the evaporation process.. The sea water is left in shallow ponds in the sun. The Sun's heat is gained by the sea water, causing the water to evaporate. As the water evaporates, the salt is left behind and collected as crystals. So heat is gained by the seawater during the evaporation process.

Question 29

Gopal has four magnets, E, F, G and H, as shown below. To compare the strength of the magnets, he put each of the magnets near a tray of pins. The table below shows the number of pins attracted by the magnets, E, F, G and H, from various distances. Which of the following statements is definitely correct?

Accepted Answer

C. E is a stronger magnet than F.. E attracted 10 pins from 5 cm while F attracted 10 pins from a nearer distance of 4 cm. Since E attracted the same number of pins from a greater distance, E is the stronger magnet than F, so C is definitely correct. The other comparisons involve different distances and pin counts that are not controlled, so they cannot be concluded with certainty.

Question 30

Chandru was told to select the best materials for making raincoats and helmets based on the classification chart below. He was also told not to choose the same materials for making the items. Which of the following shows the best materials for making the raincoats and helmets?

Accepted Answer

D. Raincoats V, Helmets Y. A raincoat must be waterproof and flexible, and should not melt easily (high melting point) — that is material V. A helmet must be waterproof, non-flexible (rigid), strong, and ideally a poor conductor of heat for comfort — that is material Y. Since the items must use different materials, the best choice is raincoats V and helmets Y, matching option (4).

P6 Science SA1 2016 — Tao Nan

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P6 Science SA1 2016 — Tao Nan

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