Question 1

Study the living things in the tank below. Based on the diagram above, which statement(s) is/are correct?
A Fish P forms one population.
B The plants in the tank are organisms.
C The sea snails form three communities.

Accepted Answer

(2) B only. A is wrong — a single fish cannot form a population (a population needs ≥2 organisms of the same kind). C is wrong — the sea snails of the same kind together form ONE population, not three communities. B is correct because plants are living things (organisms). So only B is correct, giving option (2).

Question 2

The graph below shows the effect of temperature on the population of 4 different organisms, A, B, C and D. [Graph: x-axis Temperature (°C) 10–50, y-axis Population size. A rises sharply between ~30–40°C then falls steeply to 50°C; B rises steadily as temperature increases; C is a flat horizontal line at high population; D decreases as temperature rises] Based on the graph above, which of the following statements is correct?

Accepted Answer

(3) Population of organism B increases when the temperature increases.. From the graph, B's line rises as temperature increases, so (3) is correct. A's biggest increase is around 30–40°C (not 22°C), C's population is least affected (it is constant), and D decreases with rising temperature. So the answer is (3).

Question 3

Study the food web below and answer questions 3 and 4. [Food web: K→M→N→O; K→P; L→P; P→Q; Q→O; Q→S; R→O; R→Q] How many food producers are there in the food web above?

Accepted Answer

(3) 3. Producers are organisms with no arrows pointing INTO them (nothing eats producers from outside the chain). Looking at the web, K, L and R have no arrows pointing into them, so there are 3 producers.

Question 4

[Refer to the food web in ____] Which of the following statements is correct?

Accepted Answer

(2) P, Q and S are consumers.. P, Q and S all have arrows pointing into them from other organisms (they eat other organisms), so they are consumers — (2) is correct. O eats Q (animal) and is not only an animal eater because it could trace plant sources; M eats only K (a producer), but N also eats only M (an animal), so (3) is wrong. (4) is wrong because N is only an animal eater.

Question 5

The food relationship between four organisms is shown below. W → X → Y → Z. Based on the food chain, which statement(s) is/are correct?
A  W is the prey of X.
B  Y is the predator of Z.
C  Y is both prey and predator.
D  There are only 2 predators in the food chain.

Accepted Answer

(1) A and B only. A is correct (W is eaten by X, so W is the prey of X). B is wrong (Z eats Y, so Z is the predator of Y, not the other way around). C is correct (Y eats X and is eaten by Z). D is wrong (X, Y and Z are predators — 3 predators). So A and C only → option (1).

Question 6

Which of the following statements is an example of behavioural adaptation?

Accepted Answer

(2) Squirrels collect and store food for winter.. Behavioural adaptations are actions/behaviours an animal does (not body parts). Squirrels collecting and storing food is a behaviour. Sharp claws, shells and large ears are structural (body) adaptations.

Question 7

Some birds swim in the water. Which of the following feet helps the bird swim fast in the water? [Images: (1) a foot with three forward toes and a small back claw, no webbing; (2) a foot with sharp talons (raptor-like); (3) a slender perching foot; (4) a webbed foot]

Accepted Answer

(4) [Webbed foot]. Webbed feet have skin between the toes that increases the surface area pushing against the water, allowing the bird to swim fast. Only (4) shows webbed feet.

Question 8

John found plant X in a windy desert. The plant is short and has thin leaves. Which of the following gives the correct adaptation of Plant X and how it helps Plant X to survive in a windy desert?

Accepted Answer

(4) Grow closer to the ground / To prevent the wind from blowing plant X over.. Growing close to the ground gives the plant a low profile so strong winds cannot easily blow it over. (1) is wrong because thin leaves reduce water loss; (2) and (3) are wrong because plants need MORE light for photosynthesis, not less.

Question 9

The diagram below shows the amount of substance X being transported in the human body. Which of the following could correctly represent systems A and B and substance X?

Accepted Answer

(4) System A: digestive / System B: circulatory / Substance X: digested food. Digested food is produced in the digestive system and absorbed into the circulatory system, which carries it to other parts of the body. So System A (sends more substance X to System B and to other parts) is the digestive system, System B is the circulatory system, and substance X is digested food.

Question 10

The table below shows some information about three types of fuel, X, Y and Z, that can be burnt to produce energy. Based on the information in the table above, which of the following cannot be concluded?

Accepted Answer

(1) Acid rain forms only from the burning of X.. The table only shows the amount of energy and greenhouse gases produced — it gives no information about acid rain or which fuel causes it. So (1) cannot be concluded from the table.

Question 11

A scientist recorded the average yearly temperature of Country P over the last 20 years as shown in the graph below. [Line graph: x-axis Year 2005–2025, y-axis Temperature (°C) 32.0–33.2. Line rises steadily from about 32.4°C in 2005 to about 32.9°C in 2025] Which of the following activities could have caused the change in the temperature as shown in the graph above?
A  Picking up litter from the ground
B  Travelling on the road in petrol vehicles
C  Clearing of forests by cutting down trees
D  Turning off the tap when soaping the hands

Accepted Answer

(3) B and C only. The graph shows rising temperatures (global warming). Burning petrol in vehicles (B) releases greenhouse gases like carbon dioxide; cutting down trees (C) reduces the amount of carbon dioxide absorbed by plants. Both contribute to global warming. A and D are good environmental habits but do not cause warming.

Question 12

The diagram below shows three different kinds of fruits. [Images: Fruit A has a fibrous husk; Fruit B has a wing-like structure; Fruit C has hook-like structures] Which of the following correctly identifies the dispersal method for fruits A, B and C?

Accepted Answer

(4) Fruit A: water / Fruit B: wind / Fruit C: animal. A fibrous husk traps air and helps the fruit float on water (water dispersal). A wing-like structure helps the fruit be carried by wind. Hook-like structures attach to animal fur for dispersal by animals. So A=water, B=wind, C=animal.

Question 13

The diagram below shows the female reproductive system. Which of the following correctly match the parts to its functions?

Accepted Answer

(4) Part that produces eggs: D / Part where fertilised egg develops: B. The ovary (D, located laterally) produces eggs. The fertilised egg implants and develops in the uterus (B). So the correct match is D / B → option (4).

Question 14

Marlin made a cut on the stem of a plant to remove the food carrying tube. He watered the plant daily and left it in a place with light as shown in the diagram below. Which of the following would Marlin made most likely observe after 2 weeks?
A The fruits would become smaller and are less juicy.
B Only the top part of the cut stem would become swollen.
C Both the top and bottom parts of the cut stem would become swollen.

Accepted Answer

(3) A and B only. With the phloem removed, food (sugars) made in the leaves cannot travel downwards past the cut, so food accumulates above the cut — the top part swells (B is correct). Below the cut, the fruits/lower part receive no food, so the fruits stay smaller and less juicy (A is correct). C is wrong because the bottom part does not swell. So A and B only → option (3).

Question 15

Amy released a ball at point A. It rolled past point B to point C before rolling back. Which of the following statements correctly states the amount of kinetic and potential energy that the ball had at different points?

Accepted Answer

(3) The ball had more potential energy at point C than point B.. Potential energy depends on height. Point C is higher than point B (which is at the bottom), so the ball has more potential energy at C than at B. (1) is wrong because C is above the lowest point so PE is not zero. (2) is wrong because A is higher than C. (4) is wrong because at A (released) the ball has no kinetic energy, while at B it has the most KE.

Question 16

A ball moves down the smooth slope of a wooden plank as shown in the diagram below. When the ball hits block L, block L moves along surface M and then it stops at position N. The following changes were then made to the set-up above and tested individually.
A Decrease the mass of block L
B Increase the height of the slope
C Increase the width of the wooden plank
D Decrease the roughness of the surface M
Which of the following change(s) would make block L move further than position N?

Accepted Answer

(2) A, B and D only. A: Less mass means less friction and easier to push, so L moves further. B: Higher slope gives the ball more potential energy → more KE → harder hit on L → L moves further. D: Less rough surface means less friction, so L slides further. C: Increasing the width of the plank does not change the energy of the ball, so it has no effect. So A, B and D only → option (2).

Question 17

Two identical objects were placed separately on two similar springs made of different materials as shown below. The springs were of the same length at the start of the experiment. Which of the following about the springs is correct?

Accepted Answer

(4) The gravitational force exerted on both springs by the object is the same.. Both objects have the same mass (500 g), so the gravitational force (weight) acting on each spring through the object is the same → (4) is correct. Spring R is compressed MORE for the same force, meaning it is less stiff (more easily compressed), making (1) and (2) wrong. The force exerted is the same, so (3) is wrong.

Question 18

Fabian kicked a toy upwards. The toy travelled from point X, where Fabian's shoe hit the toy, to reach the highest point at point Z as shown below. Which of the following best describes the forces acting on the toy from point X to point Z?

Accepted Answer

(4) At point X, the gravitational force acting on the toy is less than the push force of the kick on the toy.. At point X, the kick gives the toy a push force greater than gravity, allowing it to move upwards — so (4) is correct. Gravitational force on the toy is the same at all points (mass doesn't change), so (2) is wrong. At point Y the toy is still moving up, opposite to gravity, so (3) is wrong. Gravity acts on the toy at every point including X, so (1) is wrong.

Question 19

Two bulbs lit up when connected in an electrical circuit as shown below. Which of the following circuit diagram(s), A, B, C or D, can represent the electrical circuit? [A: two bulbs in parallel with battery; B: bulb and battery wired with crossing wires; C: two bulbs in series with battery; D: a bulb in series with the battery, with a bulb appearing on the outer loop]

Accepted Answer

(3) C and D only. In the actual photographed setup, the two bulbs appear to be connected in series with the battery (one continuous loop). Diagram C shows two bulbs in series with a battery — both bulbs will light up. Diagram D, although unusual, shows the bulbs and battery forming a complete circuit where the bulbs would light. A and B do not correctly model this arrangement. Per the answer key, the correct option is (3) C and D only.

Question 20

Identical bulbs and batteries are used to set up the circuits below. Which of the following correctly identified the total number of bulbs that lit up in both circuits?

Accepted Answer

(2) 2 bulbs. In the left circuit only one bulb is in the working loop (the other is short-circuited) — 1 bulb lights. In the right circuit, considering the short-circuited bulbs from the wiring, only 1 bulb is in a complete circuit and lights — for a total of 2 bulbs lit across both circuits.

Question 21

The following shows the energy changes in a bulb.
Electrical energy → Light energy + Heat energy
Nasri would like to use a bulb that will allow him to conserve electrical energy. He has identified two suitable bulbs, G and H. He conducted an experiment on the two different bulbs and the results are shown below. Which of the following best explains his choice?

Accepted Answer

(1) G / It is cooler and thus less electrical energy is converted to heat energy.. To conserve electrical energy, less should be wasted as heat. Bulb G has a much lower surrounding air temperature (30°C vs 52°C), meaning less electrical energy is converted to heat. The two bulbs produce nearly the same amount of light, so G wastes less energy. The reason in (2) is wrong because G is not brighter than H.

Question 22

John attended a performance with his family. They are seated among the audience. Which of the following is the reason why John could not see the performers who are getting ready behind the stage curtain?

Accepted Answer

(4) The curtain did not allow light to pass through.. The curtain is opaque — it does not let light pass through, so reflected light from the performers behind the curtain cannot reach John's eyes, and he cannot see them.

Question 23

A block of ice was placed in an empty plastic cup and left in the kitchen at room temperature. Which of the following is correct about the setup above?

Accepted Answer

(3) The ice gained heat from the surrounding air.. Heat always flows from a warmer to a cooler object. The ice (at 0°C) is colder than the surrounding air (room temperature), so the ice GAINS heat from the surrounding air. This is why some ice has already melted into water at 0°C.

Question 24

Shuyi heated some ice cubes in a beaker using a hotplate. After 10 minutes, all the ice cubes melted. After another 10 minutes, the water started to boil. She then turned off the hotplate 10 minutes after the water started to boil. Which of the following graphs correctly shows the temperature of the contents in the beaker? [Four graphs all showing temperature (°C) vs time (min) over 0–40 min with various plateaus]

Accepted Answer

(2) [Rises to 100°C at 20 min, plateau to 30 min, then drops]. Per the suggested answer key, the correct graph is (2). The water reaches 100°C at 20 min (after ice has melted and water has heated up), boils with a plateau at 100°C while heated, then the hotplate is turned off and temperature drops. Per the key, option (2) is selected.

Question 25

Which of the following is not matter?

Accepted Answer

(2) Heat. Matter has mass and occupies space. Heat is a form of energy, not matter — it has no mass or volume. Oil (liquid), steam (gas) and candle (solid) are all matter.

Question 26

The diagram below shows a container with a capacity of 500 cm³ at the start of the experiment. Using the pump, 50 cm³ of water is first added to the container. Then, 50 cm³ of air is added to the container. Which of the following correctly shows the changes in the mass and volume of air in the container as compared to the start of the experiment?

Accepted Answer

(4) Mass of air: Increase / Volume of air: Decrease. After adding 50 cm³ more water, water volume = 150 cm³, so air must occupy 500 − 150 = 350 cm³ (decreased from 400 cm³). Then 50 cm³ more air is added → mass of air increases. So volume of air decreased and mass of air increased — option (4).

Question 27

Refer to the diagram and information below to answer questions 27 and 28. Object K was lowered to distance d above a pile of steel pins as shown below. The number of steel pins attracted by object K was recorded. The experiment was repeated by increasing distance d each time. The bulb remained lit throughout the experiment. [Table: d=5 cm → 19 pins; d=10 cm → 13 pins; d=15 cm → 5 pins; d=20 cm → 0 pins] Based on the results, which of the following statements on the experiment is/are correct?
A Object K is made of a non-magnetic material.
B When distance d is 20 cm, object K is not an electromagnet.
C As distance d increases, the number of steel pins attracted decreases.
D As distance d decreases, the gravitational force acting on the steel pins decreases.

Accepted Answer

(1) C only. From the table, as d increases from 5 to 20 cm, the number of pins attracted decreases from 19 to 0 — so C is correct. A is wrong: Object K must be magnetic (electromagnetic) to attract pins. B is wrong: the bulb stays lit, so current still flows and K is still an electromagnet — it just cannot attract pins at 20 cm because they are too far. D is wrong: gravitational force depends on mass and Earth's gravity, not the distance between K and the pins. So only C is correct → option (1).

Question 28

The experiment was repeated by replacing object K with object L. The bulb remained lit throughout the experiment. The table below shows the results. Which of the following explains the results?

Accepted Answer

(2) Object L is made of wood.. The bulb remained lit, so electricity does flow through the coils — but no steel pins are attracted at any distance. This means object L is not made of a magnetic material (e.g., iron), so the coil cannot become an electromagnet. Wood is non-magnetic, so option (2) explains the results.

P6 Science SA2 2025 — Nanyang

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