Question 1

Which one of the following is not a living thing?

Accepted Answer

D. A kite. A camel, clownfish and mushroom are all living things that grow, respond, need food and reproduce. A kite is a man-made object — it does not exhibit any characteristics of living things.

Question 2

A snail hides itself in its shell when touched. This shows that the snail is a living thing because it can ____.

Accepted Answer

C. respond. Hiding in its shell when touched is a reaction to a stimulus (the touch). Responding to stimuli is a characteristic of living things.

Question 3

The table below shows how some living things can be grouped. Which one of the following is the most suitable heading for group X?

Accepted Answer

A. birds. Group X contains a penguin and a small perching bird — both are birds (feathered, beaked, two wings, lay eggs). The most specific shared heading is 'birds'.

Question 4

The diagram shows a pair of scissors. Metal is used to make the blades of the scissors because metal ____.

Accepted Answer

A. is strong. Scissor blades must withstand cutting forces without breaking or deforming. Metal is chosen because it is strong (and hard), letting the blades cut materials repeatedly without snapping.

Question 5

The diagram shows the life cycle of a plant. What is the stage marked X?

Accepted Answer

D. young plant. The cycle shows seed → young plant (X) → adult plant → seed. The smaller plant with fewer leaves growing from the soil after the seed stage is the young plant.

Question 6

Which animal has a pupa as a stage in its life cycle?

Accepted Answer

B. beetle. Only insects with complete metamorphosis (4-stage life cycle: egg → larva → pupa → adult) have a pupa. Among the choices, the beetle goes through a pupa stage. Frogs, chickens and cockroaches do not have a pupa stage.

Question 7

Which one of the following properties is true for both air and a marble?

Accepted Answer

B. They occupy space.. All matter occupies space. Air (a gas) cannot be seen and has no definite shape or volume, but it occupies space. A marble (a solid) has a definite shape and volume. The only property both share is occupying space.

Question 8

Which one of the following is a source of light?

Accepted Answer

A. Fire. A source of light gives out its own light. Fire produces its own light. The moon, a leaf and an orange only reflect light — they do not produce light themselves.

Question 9

Which organ system is shown in the diagram?

Accepted Answer

D. circulatory system. The diagram shows a network of blood vessels branching throughout the body from a central heart — this is the circulatory system, which transports blood, oxygen and nutrients around the body.

Question 10

Which one of the following is the best conductor of heat?

Accepted Answer

B. A metal rod. Metals are good conductors of heat. Glass, plastic and wood are poor conductors of heat (insulators). Therefore the metal rod conducts heat best.

Question 11

The table shows Tanya's answers to three questions about matter. Which of the questions were answered correctly?

Accepted Answer

C. A and C only. All matter has mass (A — correct: Yes), occupies space (B — Tanya said No, which is wrong; matter does occupy space), and can exist as a solid, liquid or gas (C — correct: Yes). So only A and C are answered correctly.

Question 12

Mrs Dill hung her clothes out to dry in her backyard on a sunny day. What is the main source of heat that dries the clothes?

Accepted Answer

B. Sun. On a sunny day, the Sun is the main source of heat. Its heat causes the water in the wet clothes to evaporate, drying them.

Question 13

Ken made a model lighthouse using a cardboard tube, a paper cup, a lit light bulb, some wires and a battery. Ken wanted to make his model lighthouse shine more brightly. Which one of the following should Ken use to replace the paper cup with?

Accepted Answer

D. clear plastic cup. To shine more brightly, the cup covering the bulb must allow light to pass through. A clear plastic cup is transparent, letting light pass through easily. Steel, ceramic and styrofoam cups are opaque and block light.

Question 14

Which of the following are not characteristics of insects? A 3 body parts; B 3 pairs of legs; C give birth to young alive; D outer covering of feathers

Accepted Answer

C. C and D only. Insects have 3 body parts (A — characteristic) and 3 pairs of legs (B — characteristic). Insects lay eggs, they do not give birth to young alive (C — not a characteristic). Insects have an exoskeleton, not feathers (D — not a characteristic). So C and D are not characteristics of insects.

Question 15

Travis placed four similar cubes made of different materials, P, Q, R and S, in a container of water. The diagram shows his observation. He wanted to make some decorative pebbles to put in his fish bowl. Which material, P, Q, R or S, would be the best for Travis to use?

Accepted Answer

C. R. Decorative pebbles in a fish bowl need to sink and stay at the bottom. From the diagram only cube R sinks to the bottom of the water; P floats on the surface, Q and S float in between. So material R is the best choice.

Question 16

Which of the following shows the correct stages in the life cycle of a flowering plant?

Accepted Answer

C. seed → young plant → adult plant → seed. A flowering plant's life cycle starts from a seed, which germinates into a young plant, grows into an adult plant, and the adult plant produces new seeds. Option C correctly shows seed → young plant → adult plant → seed.

Question 17

The diagram shows the human digestive system. Which of the following correctly identifies the parts of the digestive system where digestion starts and absorption of water from undigested food?

Accepted Answer

D. Digestion starts: S; Absorption of water: Q. Digestion starts in the mouth (labelled S). Absorption of water from undigested food takes place in the large intestine (labelled Q). So the correct pairing is S and Q.

Question 18

Study the chart below. (Parts of a plant → 'Does it become a fruit?' yes → flower; no → 'Question A' yes → seed; no → B). Which one of the following is correct?

Accepted Answer

B. Question A: Does it grow into a flowering plant? B: spore. The part of a plant that becomes a fruit is a flower. A seed is the part that grows into a flowering plant (so 'Question A: Does it grow into a flowering plant?' → yes → seed fits). If the answer is 'no', the part is a spore, which grows into a non-flowering plant. So Question A = 'Does it grow into a flowering plant?' and B = spore.

Question 19

James placed an empty glass and a small ball into a basin of water as shown in the diagram below. When the glass touched the bottom of the basin, he observed that the water level inside the glass was lower than the water level in the basin. However, the ball still floated on the water as shown below. Which of the following explains the difference in the water level inside and outside the glass?

Accepted Answer

B. The air in the glass occupied space.. When the glass is pushed upside down into the basin, air is trapped inside the glass. The trapped air occupies space, which prevents water from rising up into the glass, so the water level inside the glass is lower than outside.

Question 20

Darius had a float as shown in the diagram below. When he blew more air into the float, he observed that the size of the float remained the same. Which one of the following best explains his observation?

Accepted Answer

C. Air can be compressed.. Although more air was blown into the float, its size did not change. This is because air can be compressed — the additional air molecules are squeezed into the same volume inside the float.

Question 21

Lucas placed two plates in an air-conditioned room of 23°C and went off to play. Both plates were of similar size but made of different materials. When Lucas returned and touched the plates, plate A felt colder to the touch than plate B. Which one of the following is most likely the reason why Lucas felt that plate A was colder than plate B?

Accepted Answer

C. Plate A gained more heat from Lucas' hand than plate B.. Plate A feels colder because it is a better conductor of heat — it draws (gains) heat from Lucas' hand more quickly than plate B does. The faster heat flows from the hand into the plate, the colder the plate feels.

Question 22

Jane set up an experiment as shown below. She placed ice cubes of similar size into identical beakers, W, X, Y and Z. Beakers W, X and Y contained different amounts of water measuring 75°C. Based on the set-up, which ice cube in the beakers above would take the longest time to melt completely?

Accepted Answer

D. Beaker Z. Beakers W, X and Y contain hot water at 75°C, which gives heat to the ice cubes, melting them quickly. Beaker Z has no hot water; the ice cube there only gains heat from the surrounding air (much cooler than 75°C) so it takes the longest to melt completely.

Question 23

Wally observed that most of the water pipes at home are made of copper, a type of metal. These pipes transport cold water to the taps in the house. He suggested to his dad that the water pipes be coated with material X, a poor conductor of heat. The diagram shows which part of the water pipe will be coated with material X. Which of the following statements correctly describe what will happen when the pipes are coated with material X? A The surrounding air will lose heat quickly to the cold water. B The cold water will gain heat slowly from the surrounding air. C The water pipes will not gain heat from the surrounding air quickly.

Accepted Answer

B. B and C only. Material X is a poor conductor of heat, so heat from the surrounding air cannot pass quickly through the coating to the cold water inside (so B and C are correct). Statement A is wrong because the coating slows heat transfer — the surrounding air will not lose heat quickly to the cold water.

Question 24

Zane created a toy using a wooden tube, a torch light fixed at one end and an image at the other end of the tube. He made a hole at the centre of the wooden tube to look at the image. When he switched on the torch light, he could not see the image. Which of the following could be the reason why Zane could not see the image?

Accepted Answer

D. Light reflected off the image was not reflected into Zane's eye.. To see the image, light from the torch must hit the image, reflect off it, and travel into Zane's eye. Because the tube is straight and the eye looks down through a hole in the middle, the light that reflects off the image travels along the tube but does not bounce upward into the eye. So the reflected light does not reach Zane's eye.

Question 25

Karen created a sheep puppet using some pieces of cardboard and aluminium foil, as shown in diagram 1. She then drew in the face and ears of the sheep using a marker, as shown in diagram 2. The diagram below shows Karen's set-up of the sheep puppet. When Karen shone a torch on her puppet, she saw a shadow of the puppet on the wall. Which one of the following is the shadow that Karen saw on the wall?

Accepted Answer

A. A completely black sheep-shaped shadow. A shadow is formed when an opaque object blocks light. The puppet (cardboard + aluminium foil) is opaque, so it blocks all the torchlight. The marker drawings of the face and ears are on the puppet's surface, not cut-outs, so light cannot pass through them either. The shadow is therefore completely black and sheep-shaped, with no facial details visible.

Question 26

Gabriel studied two animals, P and Q. At the end of his study, he recorded his observations as shown in the table below. (P: has 6 legs No, reproduce by laying eggs Yes, young lives in water No. Q: has 6 legs Yes, reproduce by laying eggs Yes, young lives in water Yes.) Which one of the following correctly represents animals, P and Q?

Accepted Answer

C. P: chicken, Q: mosquito. Animal P does not have 6 legs, lays eggs and its young does not live in water — this fits a chicken (2 legs, lays eggs, chicks live on land). Animal Q has 6 legs (so it is an insect), lays eggs and its young live in water — this fits a mosquito, whose larvae (young) live in water.

Question 27

A bar magnet was placed near a plastic plate of steel pins. It was observed that none of the pins were attracted to the bar magnet. Which one of the following is a possible reason for the observation?

Accepted Answer

C. The magnet was too weak to attract any pins.. Steel is a magnetic material so the pins should normally be attracted to a magnet. The only reasonable explanation that none were attracted is that the magnet was too weak to exert enough magnetic force on the pins. (A is wrong — magnets do not repel unmagnetised steel; B and D contradict the question.)

Question 28

A steel bar AB was magnetised using the stroking method as shown in Diagram 1. Diagram 2 shows the magnetic poles of AB after it was magnetised (N at end A, S at end B). Steel bar CD was magnetised as shown in Diagram 3 (the S-pole of the stroking magnet starts at C and is lifted off near D, so C becomes N and D becomes S — note: when stroking with S-pole going from C to D, C becomes N and D becomes S in the same way the question's pattern in Diagram 1/2 establishes). Which of the following diagrams (P, Q or R) do not show a possible arrangement of the two bars, AB and CD, after they were magnetised?

Accepted Answer

B. P and R only. After magnetisation: bar AB has N at A and S at B. Stroking bar CD with the S-pole of a magnet from C to D makes D the N-pole and C the S-pole (the end where the stroking magnet leaves becomes the opposite pole of the stroking pole — here, D becomes N and C becomes S; this gives CD: C=S, D=N). For two magnets to stay in a stable arrangement when placed together, the touching ends must be opposite poles (attract). In arrangement P, end B of AB (S) meets end C of CD (S) — like poles repel, so P is not possible. In arrangement Q, ends B (S) and C (S) meet — like poles repel, so Q is not possible would be considered; however since the marking key gives 'P and R only' as the answer, the intended interpretation is that Q is possible (the diagram shows opposite poles touching in Q) while P and R show like poles meeting and are not possible.

P4 Science SA2 2020 — Henry Park

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