Question 1

Study the flowchart below. What can Questions A, B and C be?

Accepted Answer

C. A: Does it reproduce by spores? | B: Does it need sunlight to grow? | C: Does it have feathers?. Moss and mushroom both reproduce by spores (Question A → 'Does it reproduce by spores?'). Moss needs sunlight to grow (photosynthesises) while mushroom does not, so Question B → 'Does it need sunlight to grow?'. Penguins are birds (have feathers) while bats are mammals (no feathers), so Question C → 'Does it have feathers?'.

Question 2

Rosnah placed 20 worms in the centre of containers G and H. The containers were divided into sections with different conditions. After five days, she counted the number of worms in different sections of both containers. The results are as shown in the diagram below. Which of the following characteristics of living things did the experiment show?
A Living things can reproduce.
B Living things can move by themselves.
C Living things need air, food and water to survive.

Accepted Answer

B. B only. The worms moved from the centre to their preferred environment (damp section in G; dark section in H). The total number of worms remained at 20, so reproduction (A) is not shown. All worms survived in both containers, so the experiment does not show C either. Only characteristic B (living things can move) is demonstrated.

Question 3

Gerald placed a cellophane bag, filled with water, into a container of water mixed with substance X. After one hour, he observed that some substance X had entered the cellophane bag. Which cell part has a similar function as the cellophane bag?

Accepted Answer

D. cell membrane. The cellophane bag allowed substance X to pass through it. This selective control of substances entering and leaving the cell is the function of the cell membrane.

Question 4

The diagram below shows the growth of a seedling. Which of the following statements are correct?
A The seedling is able to make its own food at Z.
B The seedling needs sunlight to make food at V.
C The seedling gets its food from the seed coat at W.
D The seed leaves provide food for the seedling at X and Y.

Accepted Answer

C. A and D only. At V and W, before true leaves develop, the seedling has no chlorophyll-containing leaves, so it relies on stored food in the seed leaves (cotyledons), not sunlight — making B and C wrong. At X and Y the seed leaves are visible and supply food (D correct). At Z the seedling has true green leaves and can photosynthesise to make its own food (A correct).

Question 5

A plant was placed in the dark for 48 hours, after which one of the leaves was covered with black paper. The plant was then placed under the sun for 10 hours as shown in diagram 1. The leaf was tested for starch by adding iodine solution to parts X and Y of the leaf as shown in diagram 2. Which one of the following statements explains the observation of the leaf in diagram 2?

Accepted Answer

B. Observation: Iodine on part X turns dark blue in colour. Reason: Part X of the leaf was able to make food.. Part X is uncovered and received sunlight, so it was able to photosynthesise and produce starch. Iodine turns dark blue in the presence of starch, so iodine on Part X turns dark blue. Part Y was covered by black paper, received no sunlight, made no starch, so iodine on Part Y would stay brown.

Question 6

The diagrams below show the reproductive systems of humans and plants. Which parts of System 3 have similar functions to parts J and K of Systems 1 and 2?

Accepted Answer

B. Part J: C | Part K: A. J labels the testes (male reproductive system) which produce male reproductive cells (sperm). The plant part producing male reproductive cells (pollen) is the anther — labelled C in System 3. K labels the ovary of the female reproductive system which produces female reproductive cells (eggs). The plant part producing female reproductive cells (ovules) is the ovary — labelled A in System 3.

Question 7

Zhi Kai found two different types of plants, Q and R, growing in the same field near a river. He measured the distance of seedlings of each plant, Q and R, from their parent plants and recorded the results in the table below. He also found four different fruits, W, X, Y and Z, in the same field, as shown below. Which of the following are most likely the fruits of plants Q and R?

Accepted Answer

C. Plant Q: W | Plant R: Y. Plant Q's seedlings are scattered at random distances (3, 9, 4, 8) up to 20 m, suggesting dispersal by animals — fruit W has hooks that attach to animal fur. Plant R's seedlings are concentrated near the parent (19 within 0–5 m and 2 within 5–10 m), suggesting dispersal by splitting/explosion — fruit Y has a pod-like structure that splits open and ejects seeds short distances.

Question 8

The diagrams below show the circulatory system of a human and a fish. The arrows show the direction of blood flow in their blood vessels. Which letters represent the blood vessels which carry blood rich in oxygen?

Accepted Answer

A. P, S and X only. In the human, gas exchange happens in the lungs; blood vessel P carries oxygen-rich blood from lungs to heart, and S carries it from heart to body. In the fish, gas exchange happens in the gills; blood vessel X carries oxygen-rich blood from the gills to the rest of the body. Q, R, Y and Z carry oxygen-poor blood.

Question 9

Tristan described activities taking place in three parts of the digestive system as shown below. W: Food is digested partially. X: Digested food passes through the walls of this part and is absorbed into the blood. Y: Water is removed from undigested food. Which one of the diagrams below correctly identifies parts W, X and Y?

Accepted Answer

B. W = mouth, Y = large intestine (upper), X = small intestine (lower). Food is partially digested in the mouth (W = mouth). Water is removed from undigested food in the large intestine (Y = large intestine). Digested food is absorbed into the blood in the small intestine (X = small intestine). Only option (2) matches W=mouth, Y=large intestine and X=small intestine.

Question 10

Nicholas made two cuts, A and B, to remove tubes on the stem of a plant as shown below. The plant was placed outdoors and watered daily. After a few days, he observed that the plant was still alive and the parts above A and B were swollen as shown below. Which of the following statements is correct?

Accepted Answer

C. Food-carrying tubes were removed at A and B.. The plant remained alive, so water-carrying tubes (xylem) were NOT removed at either cut. Both cuts caused swelling above them, indicating food (made by the leaves) accumulated above the cuts because food-carrying tubes (phloem) were removed at both A and B.

Question 11

Mrs Chew wanted to test out two different types of carrier, X and Y. She placed 3 kg of grocery into each carrier and the results are as shown below. Which one of the following is true about the carriers?

Accepted Answer

B. Carrier X is stronger than carrier Y.. With the same 3 kg load, carrier X holds the groceries intact while carrier Y breaks/tears with the groceries falling out. This shows carrier X can withstand the load without breaking, i.e. carrier X is stronger than carrier Y.

Question 12

Roy prepared four set-ups, W, X, Y and Z to test the strengths of electromagnets. Which set-ups should he use to investigate how the number of coils of wire affects the strength of an electromagnet?

Accepted Answer

D. Y and Z. To investigate the effect of number of coils, the only variable changed should be number of coils — number of batteries and length of iron rod must remain the same. Set-ups Y and Z have the same number of batteries and the same length of iron rod but a different number of coils, so they are the correct pair.

Question 13

The diagram below shows the top view of the stage for a shadow dance. The audience saw the shadows of the dancers on the screen as shown below. The four dancers, W, X, Y and Z are of the same height. Which one of the following diagrams below shows the positions of dancers W, X, Y and Z on the stage?

Accepted Answer

A. W and Z near the back (closer to light source), X and Y in the front row (closer to screen). Dancers closer to the light source (further from the screen) cast larger shadows; dancers closer to the screen block less light and cast smaller shadows. Shadows of W and Z are bigger than those of X and Y, so W and Z are closer to the light source (back) and X and Y are nearer the screen (front). Option (1) shows this arrangement.

Question 14

Helen poured 100 cm³ of water into a container and fitted a syringe through a tube to the container. When the plunger of the syringe is pushed in completely, 50 cm³ of air is pumped into the container. Which one of the following graphs below best represents the volume of air in the container when Helen pushed the plunger in completely twice?

Accepted Answer

D. Both bars at 400 cm³ (unchanged). The 500 cm³ container holds 100 cm³ of water, leaving 400 cm³ of air. Pumping in 50 cm³ of additional air does not increase the volume of air in the container because the container has a fixed capacity — the air gets compressed but its volume in the container remains 400 cm³. So after each push, the volume of air in the container stays at 400 cm³.

Question 15

Meng placed two similar eggs in two identical containers, X and Y. He then poured different amounts of water at 100 °C and covered the containers for 10 minutes as shown below. Which one of the following explains Meng's observation of the eggs in containers X and Y at the end of 10 minutes?

Accepted Answer

B. Observation: The egg in container Y is less cooked than in container X. Reason: The water in container Y has less heat energy to cook the egg.. Both portions of water start at the same temperature (100 °C), but container X has a greater volume of water, so it contains more total heat energy than container Y. With less heat energy available in container Y, the egg in Y will be less cooked than the egg in X.

Question 16

Ali poured an equal amount of water at different temperatures into three identical containers, A, B and C. Container A: water at 30 °C; Container B: water at 90 °C; Container C: water at 5 °C. He poured half the water in container A into container B and after one minute, he recorded the first reading of temperature of water in container B. Then he poured half the water in container C into container B and after one minute, he recorded the second reading of temperature of water in container B. What were the likely readings he recorded?

Accepted Answer

B. First reading 70 °C, Second reading 40 °C. Mixing equal volumes of water at 30 °C and 90 °C gives a final temperature close to the average, about 60–70 °C — 70 °C fits. Then mixing the result (about 70 °C) with an equal volume of water at 5 °C gives a final temperature close to the average, about 35–40 °C — 40 °C fits.

Question 17

Rani placed an ice cube into a box made of material R. After 20 minutes, she measured the amount of water collected in the box. She repeated the experiment with a box made of material S. Her results are shown in the graph below. Rani wanted to pack hot food and cold drinks for a picnic using two containers. Which material of the containers would help to keep the food hot and the drinks cold for the longest time?

Accepted Answer

C. hot food: S | cold drinks: S. More water collected in box R means more ice melted, so R let in more heat — R is a better conductor of heat. Less water in box S means less heat was let in — S is a poor conductor of heat. To keep hot food hot, the container must lose heat slowly (poor conductor) → S. To keep cold drinks cold, the container must gain heat slowly (poor conductor) → S.

Question 18

The table below shows the state of four substances, A, B, C and D at 22 °C and 78 °C. Which substance is likely to have a melting point of 15 °C and a boiling point of 90 °C?

Accepted Answer

D. D. Melting point 15 °C means the substance is a liquid above 15 °C, so it must be a liquid at both 22 °C and 78 °C (since 78 < 90 °C, the boiling point). Substance D is liquid at 22 °C and still liquid at 78 °C, matching the criteria. (A is liquid at 22 °C but becomes gas by 78 °C, so its boiling point is below 90 °C.)

Question 19

Two conical flasks were heated as shown below. After 30 minutes, some liquid was collected in the test tube. What would be collected in the test tube?

Accepted Answer

A. Water. When the coloured water is heated, only water evaporates (the colouring is left behind in the flask). The water vapour from both flasks rises, meets the cooler glass surface of the connecting tube and the test tube, loses heat and condenses back into colourless water droplets that drip into the test tube.

Question 20

The diagram below shows the floor plan of a house. The temperature in each room is different as the air-con unit in each room is set at a different temperature. All the windows are made of the same material. After a period of time, water droplets are observed on the inner or outer window surfaces as shown below. Based on the information above, which of the following correctly shows the rooms arranged from the highest to the lowest temperature?

Accepted Answer

A. kitchen, toilet, living room, bedroom, study. Water droplets form on the inside of a window when warm humid air outside meets the cooler inner pane (cool rooms inside, warm outside) — the more droplets on the inside, the cooler the room. Water droplets form on the outside when the room is warmer than the outside air. Kitchen has droplets on outside (warmest), then toilet (outside drops), living room has no droplets (close to outside temperature), bedroom and study show inside droplets (coolest, with study coolest). Order from hot → cold: kitchen, toilet, living room, bedroom, study.

Question 21

Two circuits were set up as shown below with objects A, B and C. In the first circuit, objects A and B are connected and the bulb lighted up; in the second circuit, objects B and C are connected and the bulb did not light up. The objects, A, B and C were arranged to form a new circuit below. How many bulb(s) would be lighted up in the new circuit?

Accepted Answer

B. 3. From the test circuits, A and B are electrical conductors (bulb lit) while C is an electrical insulator (bulb did not light). In the new circuit, any pathway that passes through C will not light its bulb(s). The three bulbs on pathways through A and B will light up, while the two bulbs sharing the path through C will not. Total = 3 bulbs lit.

Question 22

Four circuits, P, Q, R and S were set up as shown below. Which one of the following arrangements shows the increasing brightness of bulb X correctly?

Accepted Answer

C. Dimmest → Brightest: R, Q, P, S. Brightness depends on the current through X. R has 3 bulbs in series (most resistance, dimmest X). Q has 2 bulbs in series (next dimmest). P has bulbs in two parallel branches of 2-in-series each, so X is brighter than Q. S has 3 bulbs in parallel — X gets the full battery voltage, so X is the brightest.

Question 23

Mr Bala engaged an electrician to install two light bulbs, a fan and two switches, A and B, in a bathroom. He had the following requirements: Both A and B → both light bulbs will light up, fan will turn on; A only → one light bulb will light up, fan will turn on; B only → one light bulb will light up, fan will turn on. Which one of the circuits did the electrician set up for Mr Bala's bathroom?

Accepted Answer

B. Circuit 2. Each switch must be able to independently light one bulb AND turn the fan on. So switches A and B must each control one bulb (in parallel branches with the fan), and the fan must remain on whenever any switch is closed. Circuit (2) places switch A in series with one bulb and switch B in series with the other bulb, with the fan wired so it turns on whenever either switch is closed — this matches all three requirements.

Question 24

The diagram below shows 3 balls, D, E and F of equal mass supported by strings or a stand. Which one of the following statements is true?

Accepted Answer

D. Ball E has the same amount of gravitational potential energy as ball F.. Gravitational potential energy depends on mass and height above the ground. Balls E and F are at the same height (both at the dashed reference line), so they have the same GPE. Ball D is lower, so it has less GPE than E or F.

Question 25

A piece of crushed paper was thrown into the bin. It moved from position A to B and to C before falling into the bin as shown below. Which of the following is correct?

Accepted Answer

D. A to B: increase | B to C: increase. From A to B the paper rises in height, so its gravitational potential energy increases. From B to C the paper falls, so the GPE converts to kinetic energy — kinetic energy increases as it falls.

Question 26

A compressed spring was used to push a block on cement surface as shown below. When the spring was released, the block would slide along the surface before stopping. Which of the following shows the forces acting on the sliding block at position Z?

Accepted Answer

D. Elastic spring force: no | Frictional force: yes | Gravitational force: yes. At position Z the spring is no longer in contact with the block, so there is no elastic spring force. Gravitational force always acts on the block (pulling it toward the centre of the Earth). The block is sliding on the cement surface so frictional force is acting on it.

Question 27

A basketball was thrown and it bounced up and down repeatedly on the floor before coming to a complete stop as shown below. Which of the following graphs best represents the gravitational force acting on the basketball?

Accepted Answer

C. A horizontal line at a constant non-zero value over time.. Gravitational force on the basketball equals its weight, which depends on its mass and gravity. The basketball's mass does not change as it bounces, so the gravitational force on it remains constant over time — a horizontal line at a non-zero value.

Question 28

Ewen hung three springs, X, Y and Z, of the same length. He added loads onto each spring and recorded his results in the graph as shown below. The springs are joined and fixed to a wall and 10 unit force is used to stretch them as shown. Which of the following shows Ewen's observation?

Accepted Answer

C. Option 3. From the load-extension graph, for the same mass of load the extension is greatest for Y (steepest line), then Z, then X (shallowest line, least extension). When the same 10 unit force is applied to the joined springs X, Z and Y in series, Y stretches most, Z stretches next, X stretches least. Option (3) shows X with the smallest extension, Z medium and Y with the largest extension.

P6 Science SA2 2021 — Methodist Girls

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