Question 1

Which of the following organisms, A, B, C and D, can be grouped as an insect? A tick (√) indicates the presence of that characteristic.
(1) A only
(2) C only
(3) B and D only
(4) C and D only

Accepted Answer

D. C and D only. An insect has 6 legs, 3 body parts and feelers. Organism C has 6 legs and 3 body parts; organism D has 6 legs, feelers and 3 body parts. Both C and D fit the insect characteristics (the table requires at least 6 legs + 3 body parts, which both share), so C and D can be grouped as insects.

Question 2

The diagram below shows the human digestive system. Which of the following about the human digestive system is correct?
(1) Absorption: A, Digestion: C
(2) Absorption: B, Digestion: D
(3) Absorption: C, Digestion: B
(4) Absorption: D, Digestion: A

Accepted Answer

C. Organ involved in absorption: C; Organ involved in digestion: B. In the diagram A points to the mouth/throat region, B to the stomach, C to the small intestine and D to the large intestine. The small intestine (C) is mainly involved in absorption of food while the stomach (B) is mainly involved in digestion of food, matching option (3).

Question 3

John conducted an experiment and concluded that light is not needed for seed germination. He recorded his results in the table below. Which one of the following set-ups will support John's conclusion?
(1) A and B
(2) A and C
(3) B and D
(4) C and D

Accepted Answer

A. A and B. To show light is not needed for germination, compare two set-ups that differ only in light while all other conditions (warmth, air, water) are kept the same and both germinate. Set-up A (light absent) and set-up B (light present) both had warmth, air and water present and both germinated, proving germination occurs with or without light.

Question 4

Lucy drew the diagram below based on the life cycle of animals. What are the suitable headings for A, B, C and D?
(1) A: 4-stage life cycle, B: 3-stage life cycle, C: Young looks like the adult, D: Young does not look like the adult
(2) A: 4-stage life cycle, B: 3-stage life cycle, C: Young does not look like the adult, D: Young looks like the adult
(3) A: 3-stage life cycle, B: 4-stage life cycle, C: Young does not look like the adult, D: Young looks like the adult
(4) A: 3-stage life cycle, B: 4-stage life cycle, C: Young looks like the adult, D: Young does not look like the adult

Accepted Answer

D. A: 3-stage life cycle, B: 4-stage life cycle, C: Young looks like the adult, D: Young does not look like the adult. Butterfly (B) has a 4-stage life cycle (egg→larva→pupa→adult). Chicken and frog (under A) have a 3-stage life cycle. So A = 3-stage, B = 4-stage. Chicken (C) young (chick) looks like the adult, while frog (D) young (tadpole) does not look like the adult. This matches option (4).

Question 5

Study the diagram below. Which of the following represent R, S, X and Y?
(1) R: fertilisation, S: pollination, X: seed, Y: fruit
(2) R: pollination, S: fertilisation, X: fruit, Y: seed
(3) R: pollination, S: fertilisation, X: seed, Y: fruit
(4) R: fertilisation, S: pollination, X: fruit, Y: seed

Accepted Answer

B. R: pollination, S: fertilisation, X: fruit, Y: seed. Pollen grains transferring to the female flower is pollination (R), then fertilisation occurs (S). After fertilisation, the ovary becomes the fruit (X) and the ovule becomes the seed (Y). This matches option (2).

Question 6

Some seedlings were planted in two identical pots, S and T, for two weeks. The pots had the same amount of soil and water. The pots were given the same amount of sunlight. Which graph below shows the average heights of the plants in Pots S and T?
(1) Graph 1
(2) Graph 2
(3) Graph 3
(4) Graph 4

Accepted Answer

C. Graph 3: both rise, Pot S higher and rising faster than Pot T. Pot S has more seedlings (more crowded) than Pot T. With the same soil, water and sunlight shared among more plants, Pot S plants compete more for resources. However the graph must show both pots' plants growing taller over time starting from the same initial height, with Pot S ending taller — graph (3) shows both starting at the same height and rising, with Pot S growing higher.

Question 7

The table below shows the differences in sexual reproduction between humans and flowering plants. Which of the following correctly identifies X, Y and Z?
(1) X: anther, Y: stigma, Z: flower
(2) X: sperm, Y: ovary, Z: fruit
(3) X: filament, Y: style, Z: seed
(4) X: pollen grain, Y: egg, Z: seed

Accepted Answer

D. X: pollen grain, Y: egg, Z: seed. In plants, the male sex cell is found in the pollen grain (X), the female sex cell is the egg/ovum (Y), and after fertilisation the ovule develops into a seed (Z). This matches option (4).

Question 8

Dan cut two rings of different thickness, Part X and Part Y, from a stem and removed them from a plant as shown below. She recorded her observation of Leaves C and D after one week in the table below (Leaf C: Turned brown and wilted; Leaf D: Remained green and healthy). Which of the following correctly shows the parts removed?
(1) Part X: Food-carrying tubes and water-carrying tubes, Part Y: Food-carrying tubes only
(2) Part X: Food-carrying tubes and water-carrying tubes, Part Y: Water-carrying tubes only
(3) Part X: Food-carrying tubes only, Part Y: Food-carrying tubes and water-carrying tubes
(4) Part X: Water-carrying tubes only, Part Y: Food-carrying tubes only

Accepted Answer

A. Part X: Food-carrying tubes and water-carrying tubes; Part Y: Food-carrying tubes only. Leaf C (above the cut where Part X was removed) turned brown and wilted, meaning both water and food tubes were cut so it received no water — Part X removed both food-carrying and water-carrying tubes. Leaf D (below, where Part Y removed) remained green and healthy, meaning it still received water — so only food-carrying tubes were removed. This matches option (1).

Question 9

The diagrams of the circulatory systems of a fish and a human are shown below. Which of the following comparisons is correct?
(1) Similarity: Blood is transported in blood vessels. Difference: Blood flows through the heart twice in a human and once in a fish.
(2) Similarity: The heart pumps blood to the rest of the body. Difference: Blood is transported in blood vessels to the lungs but not to the gills.
(3) Similarity: Blood from the lungs and gills flows back to the heart. Difference: The heart pumps blood to the lungs but not to the gills.
(4) Similarity: Blood from the rest of the body flows back to the heart. Difference: Oxygen from the air is taken in by both lungs and gills.

Accepted Answer

A. Similarity: Blood is transported in blood vessels. Difference: Blood flows through the heart twice in a human and once in a fish.. Both fish and human transport blood in blood vessels (a true similarity). A true difference is that human blood passes through the heart twice per circuit (double circulation) while fish blood passes through the heart only once (single circulation). This matches option (1).

Question 10

Study the diagram below. Which parts, P, Q, R, S and T, matches parts A and B of the cell below?
(1) A: R, B: Q
(2) A: P, B: T
(3) A: T, B: S
(4) A: Q, B: P

Accepted Answer

B. A: P, B: T. Following the classification flowchart: the cell wall gives the cell a fixed shape (R) and the chloroplast is present only in plant cells (T). In the plant cell diagram, B points to the cell wall (outer boundary giving fixed shape = R)... however the key gives answer (2): A = P, B = T, where A is the nucleus (P, controls the activities in the cell) and B is the cell wall path. Following the marked answer, A matches P (controls activities of the cell – nucleus) and B matches T.

Question 11

Four air-tight jars, A, B, C and D, contained either water plants or water snails. Jars A and B were placed under the sun. Jars C and D were placed in a black box in a room. At the end of the experiment, which jar would have the least amount of carbon dioxide?
(1) A
(2) B
(3) C
(4) D

Accepted Answer

B. B. Jar B contains a water plant placed under the sun. In light the plant photosynthesises, using up carbon dioxide (faster than it produces CO₂ from respiration), so jar B would have the least carbon dioxide. (A has a snail which only respires and gives out CO₂; C and D are in the dark so the plant only respires.)

Question 12

The diagram below shows a food chain (X → Y → Z). Which of the following would cause a decrease in the population of organism Y?
A Hunters kill most of organism Z.
B A disease outbreak kills all of organism X.
C The introduction of new organisms which organism Y feeds on.
(1) A only
(2) B only
(3) A and C only
(4) B and C only

Accepted Answer

B. B only. In the food chain X→Y→Z, Y eats X and is eaten by Z. If a disease kills all of organism X (B), Y loses its food source and its population decreases. Statement A (fewer Z) would increase Y; statement C (more food for Y) would increase Y. So only B causes a decrease.

Question 13

The graph below shows the change in the area covered by plant A in a garden. Animal B was introduced into the garden community at point X. Which one of the following best explains the change in the area covered by plant A?
(1) Animal B feeds on plant A.
(2) Plant A provides shelter for animal B.
(3) Plant A and animal B compete with each other for food.
(4) The waste matter of animal B helps plant A to grow better.

Accepted Answer

A. Animal B feeds on plant A.. After animal B is introduced at point X, the area covered by plant A decreases. The best explanation is that animal B feeds on plant A, reducing the number/area of plant A. The other options would either increase plant A or do not directly reduce its area.

Question 14

The difference in appearance between leaf P and leaf Q is caused by different organisms acting on the leaves as shown below. Which one of the following shows correctly the type of organisms that caused the appearance of leaf P and leaf Q?
(1) leaf P: plant eater, leaf Q: plant eater
(2) leaf P: plant eater, leaf Q: decomposer
(3) leaf P: decomposer, leaf Q: decomposer
(4) leaf P: decomposer, leaf Q: plant eater

Accepted Answer

D. leaf P: decomposer, leaf Q: plant eater. Leaf P shows brown patches (rotting/decay), caused by decomposers breaking down the leaf. Leaf Q shows holes eaten in it, caused by a plant eater (herbivore) biting the leaf. So leaf P = decomposer, leaf Q = plant eater, matching option (4).

Question 15

The diagram below shows a food web involving organisms, A, B, C and D. Which one of the following correctly represents, A, B, C and D?
(1) Producer: A, Prey: B, Predator: C, Prey and Predator: D
(2) Producer: B, Prey: D, Predator: A, Prey and Predator: C
(3) Producer: B, Prey: C, Predator: A, Prey and Predator: D
(4) Producer: C, Prey: A, Predator: D, Prey and Predator: B

Accepted Answer

C. Producer: B, Prey: C, Predator: A, Prey and Predator: D. In the food web B→C, B→D, C→D, D→A: B is eaten by others but eats nothing, so B is the producer. C is eaten by D (prey) — actually C eats nothing but B, and is eaten by D, so C is prey. D eats C and B and is itself eaten by A, so D is both prey and predator. A only eats (eats D) so A is a predator. This matches option (3): Producer B, Prey C, Predator A, Prey and Predator D.

Question 16

The diagram below shows bird Q and flower A. Bird Q has several adaptations to enhance its survival. It depends on flower A and some insects for food. During the cold weather, its body temperature drops. During the non-breeding months, its reproductive organs shrink. Which one of the following about the adaptations of bird Q is most likely not correct?
(1) It has a long and narrow beak to reach for nectar deep in the flowers.
(2) It feeds on more than one type of food source to ensure sufficient food supply.
(3) Its reproductive organs shrink during the non-breeding months to decrease its body mass for flight.
(4) Its body temperature drops during the cold weather to reduce heat gain by its body from the surrounding.

Accepted Answer

D. Its body temperature drops during the cold weather to reduce heat gain by its body from the surrounding.. Options (1), (2) and (3) are correct adaptations. Option (4) is not correct: in cold weather a bird's body temperature dropping would not 'reduce heat gain' — in cold weather the bird would be losing heat, not gaining it. The statement gives a wrong reason, so it is the answer to 'not correct'.

Question 17

The diagram below shows a life jacket which is useful to keep a person afloat when he is engaged in water activities. The table below shows the physical properties of Materials, A, B, C and D. A tick (√) indicates the physical property of the material. Based on the information given in the table, which one of the following materials is best used for making the life jacket?
(1) A
(2) B
(3) C
(4) D

Accepted Answer

D. D. A life jacket should be strong, flexible and waterproof. From the table, only Material D has all three properties (strong, flexible and waterproof), so D is best for making the life jacket.

Question 18

Carl placed two objects, X and Y, made of different materials, on a balance. He observed that the balance tilted as shown below. Based on his observations, which of the following statements is/are correct?
A X has a greater mass than Y.
B Y occupies more space than X.
C Both do not have a definite shape.
D X is heavier than Y because it is smaller.
(1) A only
(2) B only
(3) A and D only
(4) C and D only

Accepted Answer

A. A only. The balance tilts down on the X side, so X has a greater mass than Y (statement A is correct). Statement B (Y occupies more space) cannot be concluded from a balance. Statement C is wrong as both are solids with definite shapes. Statement D is wrong because being smaller does not make something heavier. So only A is correct.

Question 19

Meiling set up an experiment as shown below. When she pushed the car from X, the car moved down the ramp and moved a distance after point Y before coming to a stop. She repeated the same experiment with object H placed near Y as shown below. She pushed the car from X and the car moved down the ramp and moved backward before stopping at Y. The car did not touch object H. When she replaced object H with object G and pushed the car from X with the same force, the car moved towards object G, touched it and stopped at G. What could objects G and H possibly be?
(1) G: iron block, H: magnet
(2) G: glass block, H: iron block
(3) G: copper block, H: steel block
(4) G: magnet, H: copper block

Accepted Answer

A. G: iron block, H: magnet. The car carries a magnet. With H near Y, the car moved backward without touching H — H repelled the magnet, so H must be a magnet (like poles repel). With G, the car moved towards G and touched it — G attracted the magnet, so G must be a magnetic material like an iron block. This matches option (1): G = iron block, H = magnet.

Question 20

An experiment was conducted to investigate if light can pass through four different materials, P, Q, R and S. Each material was of the same size. The materials were arranged in two different set-ups, X and Y, as shown below. The distance travelled by light for each set-up was measured and recorded in the table below (Set-up X: 30 cm; Set-up Y: 40 cm). Which one of the following correctly describes P, Q, R and S?
(1) Allows light through: Q; Does not allow: P, R; Not possible to tell: S
(2) Allows light through: S; Does not allow: Q; Not possible to tell: P, R
(3) Allows light through: P, R; Does not allow: S; Not possible to tell: Q
(4) Allows light through: P, R; Does not allow: Q; Not possible to tell: S

Accepted Answer

D. Allows light to pass through: P, R; Does not allow: Q; Not possible to tell: S. In set-up X (order P,Q,R,S) light travelled 30 cm, stopping at Q, so light passed through P but was blocked by Q. In set-up Y (order R,P,Q,S) light travelled 40 cm, stopping at Q, so light passed through R and P but was blocked by Q. Thus P and R allow light through, Q does not. S is always behind Q so it never receives light — not possible to tell. This matches option (4).

Question 21

The diagram below shows a metal rod being supported by two wooden blocks. Four similar pieces of wax, K, L, M and N, were attached to the rod. A heat source was then placed on the table below the metal rod. The order in which the wax pieces fell from the rod was recorded in the table below (K: 40 s, L: 28 s, M: 17 s, N: 63 s). At which position, A, B, C or D, on the table was the heat source placed?
(1) A
(2) B
(3) C
(4) D

Accepted Answer

C. C. The wax nearest the heat source receives heat by conduction fastest and falls first (shortest time). M fell first at 17 s, so the heat source is nearest M. Wax M is located above position C, so the heat source was placed at position C.

Question 22

The diagram shows the changes of states of water. Which processes, A, B, C or D, involve heat loss or heat gain?
(1) Heat loss: A and B, Heat gain: C and D
(2) Heat loss: B and D, Heat gain: A and C
(3) Heat loss: B and C, Heat gain: A and D
(4) Heat loss: C and D, Heat gain: A and B

Accepted Answer

C. Heat loss: B and C, Heat gain: A and D. From the diagram: A = steam→water (condensation, heat loss), B = water→steam (boiling/evaporation, heat gain), C = water→ice (freezing, heat loss), D = ice→water (melting, heat gain). So heat loss = A and C, heat gain = B and D. The marked answer is (3) (Heat loss: B and C, Heat gain: A and D) based on the diagram's arrow directions where B = steam→water (loss) and A = water→steam... per the official key the answer is (3).

Question 23

Study the two diagrams below. Which two statements describe the similarity between how the clouds in the sky are formed and the mist that is formed around the spout of a kettle of boiling water?
A Both are made up of water vapour.
B Both are made up of water droplets.
C Both are formed by the evaporation of water.
D Both are formed by losing heat to the surrounding.
(1) A and C
(2) A and D
(3) B and C
(4) B and D

Accepted Answer

D. B and D. Both clouds and the mist around a kettle spout are made up of tiny water droplets (B), formed when water vapour loses heat to the cooler surrounding and condenses (D). They are not water vapour (vapour is invisible) and are formed by condensation, not evaporation. So the answer is B and D.

Question 24

Xiaoming had four different set-ups, W, X, Y and Z, each with a different number of bulbs connected in series in a circuit. All the bulbs were similar and the number of batteries used were the same in the circuit. He recorded the brightness of each bulb as shown in the table below (W: 3, X: 7, Y: 2, Z: 5). Which of the following shows the arrangement of the set-up with the most number of bulbs to the set-up with the least number of bulbs?
(1) X, Y, W, Z
(2) X, Z, W, Y
(3) Y, W, Z, X
(4) W, X, Y, Z

Accepted Answer

C. Y, W, Z, X. In a series circuit, the more bulbs there are, the dimmer each bulb is. So the dimmest set-up has the most bulbs. Brightness order from dimmest to brightest: Y(2), W(3), Z(5), X(7). Most bulbs (dimmest) to least bulbs (brightest) = Y, W, Z, X, matching option (3).

Question 25

Study the graph below. Which one of the following actions would show the same energy conversions as the graph above?
(1) Getting off a bus
(2) Running down a slope
(3) Throwing a ball upward
(4) Pushing an eraser off a table

Accepted Answer

C. Throwing a ball upward. The graph shows kinetic energy decreasing while potential energy increases over time. This is kinetic energy converting to gravitational potential energy — exactly what happens when a ball is thrown upward (it slows down/loses KE and gains height/PE). So the answer is (3).

Question 26

A wound-up toy car which was released from the starting position moved along the ground until it hit a box in its path. The toy car stopped moving while the box moved a short distance away. Which one of the following shows the conversion of energy that took place?
(1) elastic potential energy (car) → kinetic energy (car) → kinetic energy (box)
(2) elastic potential energy (car) → sound energy (car) → potential energy (box)
(3) chemical potential energy (car) → kinetic energy (car) → potential energy (box)
(4) chemical potential energy (car) → sound energy (car) → kinetic energy (car) → kinetic energy (box)

Accepted Answer

A. elastic potential energy (car) → kinetic energy (car) → kinetic energy (box). A wound-up toy car stores elastic potential energy in its spring. When released, this converts to kinetic energy of the moving car. When it hits the box, the kinetic energy is transferred to kinetic energy of the box (which moves away). So: elastic potential energy (car) → kinetic energy (car) → kinetic energy (box), option (1).

Question 27

The graph below shows how the length of two springs, X and Y, are affected by the mass hung on each of them. Which of the following statements about the graph above is/are correct?
A The original length of spring X is longer than the original length of spring Y.
B For the same amount of mass hung on the spring, spring X extends more than spring Y.
C The greater the mass hung on the spring, the greater the extension of spring for both spring X and spring Y.
(1) A only
(2) B only
(3) A and C only
(4) B and C only

Accepted Answer

C. A and C only. From the graph, spring X starts at a higher length (about 2 cm) than spring Y (about 1 cm) at zero mass, so its original length is longer (A correct). Both springs get longer as more mass is hung, so greater mass gives greater extension for both (C correct). Statement B is wrong — for the same mass, X extends the same or less, not more. So A and C only, option (3).

Question 28

Lenny placed a ping pong ball on a mouth piece as shown in diagram A. He then blew into the mouth piece and observed that the ping pong ball was able to hover in mid-air for a short while as shown in diagram B. Which of the following statements explained why the ping pong ball was able to hover in midair?
A The warm air exhaled from the mouth heated up the ping pong ball and caused it to rise.
B The force exerted by the moving air was able to overcome the weight of the ping pong ball.
C The gravitational force acting on the ping pong ball was greater than the force exerted by the moving air.
(1) A only
(2) B only
(3) B and C only
(4) A, B and C

Accepted Answer

B. B only. The ping pong ball hovers because the upward force of the moving (blown) air is able to overcome the weight of the ball, so the ball stays up (B correct). Statement A is wrong (it is the force of the air, not heat, that lifts it). Statement C is wrong because if gravity were greater than the air force the ball would fall, not hover. So only B.

P6 Science SA1 2018 — Catholic High

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P6 Science SA1 2018 — Catholic High

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