Question 1

Which of the following characteristic(s) is/are generally common among amphibians and insects?
A They have three body parts.
B Their young look like the adults.
C They reproduce by laying eggs.
D They have smooth and moist skin.

Accepted Answer

A. C only. Both amphibians and insects reproduce by laying eggs (C). Three body parts (A) and young looking like adults are insect traits not shared by amphibians; smooth moist skin (D) is an amphibian trait not shared by insects. Only C is common to both.

Question 2

The diagrams below show a mushroom and a fern.
Which of the following comparison(s) between mushroom and fern is/are incorrect?
A Both reproduce by spores.
B Mushroom can bear flowers but not fern.
C Mushroom can make its own food but not fern.

Accepted Answer

D. B and C only. Statement A is correct (both reproduce by spores). B is incorrect (neither mushroom nor fern bears flowers). C is incorrect (mushroom is a fungus and cannot make its own food, while fern is a plant that can). The incorrect statements are B and C.

Question 3

Study the life cycles of insects, X and Y, as shown below.
Based on the diagrams above, which of the following statements are true?
A Both insects can live on land and in water.
B Both insects have different number of stages in their life cycles.
C The young of Y resembles its adult but not the young of X.
D The young of X takes a longer time to develop into the adult stage than the young of Y.

Accepted Answer

B. B and C only. Insect X is a mosquito (4 stages: egg→larva→pupa→adult, young in water); insect Y is a grasshopper (3 stages: egg→nymph→adult). B is true (different number of stages). C is true (grasshopper nymph resembles adult, mosquito larva does not). A is false (only X's young live in water) and D cannot be concluded from the diagrams. So B and C only.

Question 4

The diagram shows the life cycle of a flowering plant. The arrows are labelled 'pollination and fertilisation' (leading to B) and 'germination' (leading from B to C), with C leading back to A. Which one of the following represents stages A, B and C correctly?

Accepted Answer

D. A: adult plant, B: seed, C: young plant. Pollination and fertilisation of the adult plant (A) produce a seed (B). The seed germinates into a young plant (C), which grows back into an adult plant (A). So A = adult plant, B = seed, C = young plant.

Question 5

Which of the following statements about heredity is/are true?
A The offspring inherit traits from both parents.
B A male parent cannot pass his traits to a female child.
C The eye colour of an offspring is a trait that can be inherited from parents.

Accepted Answer

B. A and C only. A is true (offspring inherit traits from both parents). C is true (eye colour is an inherited trait). B is false (a male parent can pass traits to a female child). So A and C only.

Question 6

The diagram below shows the cross-section of a flower with parts labelled W, X, Y and Z. Four similar flowers, A, B, C and D, had some part(s) removed from them as shown in the table below. A cross (x) shows the part(s) removed. (Flower A: W removed; Flower B: Y removed; Flower C: W and Y removed; Flower D: X and Z removed.) Which flowers are still able to develop into fruits?

Accepted Answer

C. A, B and C only. W is petal, X is stamen (anther), Y is stigma, Z is ovary. A flower needs the ovary (Z) to develop into a fruit (and stigma/pollination for fertilisation). Flower D has the ovary Z removed, so it cannot develop into a fruit. Flowers A (only petal removed), B (only stigma removed) and C (petal and stigma removed) all keep the ovary, so they can still form fruits. Hence A, B and C only.

Question 7

Amanda wanted to find out if the presence of roots affects the rate of water transported up the plants. She prepared two set-ups, X and Y, using similar plants of the same height as shown below. The roots of the plant in set-up Y has been removed. Each beaker has 200 ml of red-coloured water with a layer of oil on top. Which of the following observations would allow Amanda to draw conclusion for her experiment?
A The height of growth of each plant after two hours.
B The volume of water left in each beaker after two hours.
C The time taken for both flowers in each set-up to turn red.

Accepted Answer

D. B and C only. To measure the rate of water transported, Amanda should compare how much water is taken up (volume of water left in each beaker, B) and how quickly the flowers turn red (time taken for the flowers to turn red, C). Height of plant growth (A) does not measure water transport rate. So B and C only.

Question 8

The diagram below shows the human digestive system with parts labelled W, X, Y and Z. Which of the following statement(s) is/are correct?
A Digestion ends at Z.
B There is most digested food at Y.
C There is more undigested food at W than at X.
D Digestive juices are produced at X and Z only.

Accepted Answer

B. A and C only. W is the mouth, X is the stomach, Y is the small intestine, Z is the large intestine. B is correct (digestion is completed in the small intestine Y, so it has the most digested food). C is correct (more undigested food at the mouth W than at the stomach X). A is wrong (digestion ends at the small intestine, not large intestine Z). D is wrong (digestive juices are also produced at the mouth and small intestine). So B and C only.

Question 9

The table below shows the characteristics of cells from different organisms, X, Y and Z. A tick (✓) indicates the presence of the parts of a cell. (X has nucleus, cell wall, cell membrane. Y has nucleus, cell membrane. Z has nucleus, chloroplast, cell wall, cell membrane.) Which one of the following statements is incorrect?

Accepted Answer

C. The cells of organisms Y and Z are taken from the same plant part.. Y has only nucleus and cell membrane (no cell wall or chloroplast), so it could be an animal cell (A correct). Z has a chloroplast so it can make food (B correct). All three have a cell membrane which controls movement of substances (D correct). Z has a cell wall and chloroplast but Y does not, so they cannot be from the same plant part — statement C is incorrect.

Question 10

Which one of the following graphs correctly shows how carbon dioxide affects the rate of photosynthesis?

Accepted Answer

A. A curve rising steeply then levelling off (rate increases with carbon dioxide then plateaus). As the amount of carbon dioxide increases, the rate of photosynthesis increases until another factor becomes limiting, after which it levels off. Graph (1) shows this rise-then-plateau pattern.

Question 11

Some green plants were planted in the sealed glass bottle filled with moist and fertile soil. The glass bottle was placed near the window for one week. Which of the following statement(s) is/are correct?
A The plant would die three days later as there was no air.
B The plants could only carry out photosynthesis but not respiration.
C The plants survived as there was a constant supply of air and water.
D The water in the soil would dry up and the plants would have no water.

Accepted Answer

B. C only. In a sealed terrarium near light, the plants recycle gases and water: they photosynthesise (using carbon dioxide and producing oxygen) and respire (using oxygen and producing carbon dioxide), and water is recycled through transpiration and condensation. So the plants survive due to a constant supply of air and water (C). A, B and D are all wrong.

Question 12

The diagram shows a food web. Organisms P, Q, R and S are found in the same community. The arrows show: Q→S, Q→P, P→S, P→R, S→R. Which one of the following graphs correctly represents the number of organisms present in that community?

Accepted Answer

D. P medium, Q highest, R lowest, S low. Following the arrows (which point from food to feeder), Q is eaten by P and S (Q is the producer/lowest feeder, most numerous), P is eaten by R and S, S is eaten by R, and R is the top consumer (fewest). The number of organisms decreases up the food chain, so Q is the most numerous and R is the least. Graph (4) shows Q highest and R lowest.

Question 13

Study the following food web in a field. The food web shows: Plant→V, Plant→W, Plant→X; V→T, W→Z, X→Y. The use of pesticide in the field resulted in the death of most organism V and organism W only. Which one of the following most likely shows the effect of pesticide on the population of organisms X and Z?

Accepted Answer

D. X increases, Z decreases. V, W and X all feed on the plant. When V and W die off, more plant food is available for X, so X's population increases. Z feeds on W; with W dying, Z loses its food source so Z decreases. So X increases and Z decreases.

Question 14

Porcupines are very well adapted to live in the forest. They eat leaves, twigs, buds and even barks of trees. Which one of the following is a behavioural adaptation of the porcupine that enables it to survive well in the forest?

Accepted Answer

B. They turn their backs and raise their quills in self-defense.. A behavioural adaptation is an action/behaviour (not a body part). Turning their backs and raising their quills in self-defence is a behaviour (B). Sharp claws (A), sharp teeth (C) and barbed quills (D) are physical/structural adaptations.

Question 15

The four graphs below show the changes in global sea levels over a period of time. Which one of the following most likely shows the effect of continual deforestation activities on the sea level over time?

Accepted Answer

B. Sea level increasing gradually over the years. Continual deforestation increases carbon dioxide, enhancing the greenhouse effect and global warming. This melts ice and causes sea levels to rise over time. Graph (2) shows sea level increasing over the years.

Question 16

The table below shows how the amount of sugar produced by plants is affected by light intensity. (At light intensities 70, 50, 30, 10 lux — Plant E: 37,28,19,14; Plant F: 38,20,9,2; Plant G: 38,32,27,15; Plant H: 39,23,11,3 milligrams.) Which plants are suitable to be used as indoor plants?

Accepted Answer

A. Plants E and G. Indoor plants must still produce a good amount of sugar (photosynthesise well) even at low light intensity. At 10 lux, Plant E produces 14 mg and Plant G produces 15 mg — much higher than Plant F (2 mg) and Plant H (3 mg). So Plants E and G are most suitable for low-light indoor conditions.

Question 17

Chloe set up an experiment as shown below to compare four strips of different materials, J, K, L and M, which are of the same thickness. She placed a container containing 100 cm³ of water on each strip of material and she recorded the distance, d, between the highest and lowest points of the strip, as shown in the table below. (d in mm — J: 38, K: 55, L: 5, M: 42.) Which materials are most suitable for making a food tray and a belt?

Accepted Answer

C. Food tray: L, Belt: K. The distance d shows how much each strip bends — a larger d means the material is more flexible. A food tray must be rigid (smallest bend), so material L (d = 5 mm, least flexible) is best. A belt must be flexible (largest bend), so material K (d = 55 mm, most flexible) is best. So food tray = L, belt = K.

Question 18

Jane set up the experiment below to find out about the properties of matter. A balloon is held under hot water in a container by a load. After some time, she observed both the size of the balloon and the water level in the container increased. Which one of the following explains why the water level in the container increased?

Accepted Answer

D. The air in the balloon expanded and occupied more space in water.. The hot water heats the air inside the balloon, causing the air to expand and the balloon to grow larger. The larger balloon takes up more space in the water, pushing the water level up. Mass does not change (A and C wrong); the rise is due to the expanding air in the balloon, not the water itself (B wrong). So D.

Question 19

The table below shows the melting and boiling points of two substances, P and Q. (P: melting point 55 °C, boiling point 230 °C. Q: melting point 110 °C, boiling point 180 °C.) Which one of the following shows the correct properties of substances P and Q at 200 °C?

Accepted Answer

D. P: no definite shape, Q: can be compressed. At 200 °C: P (melting 55, boiling 230) is between its melting and boiling points, so it is a liquid — a liquid has no definite shape but a definite volume. Q (melting 110, boiling 180) is above its boiling point, so it is a gas — a gas has no definite shape, no definite volume and can be compressed. So P has no definite shape and Q can be compressed.

Question 20

Two rooms, A and B, are separated by a glass window. Tiny water droplets are observed on the glass window in room A as shown below. Based on the observation above, which one of the following shows the correct temperature in each room?

Accepted Answer

B. Room A: 40 °C, Room B: 5 °C. Water droplets (condensation) form on the side of the glass where warm, moist air touches the cooler glass surface. The droplets are on the room A side, so room A must be the warmer room (warm moist air cooled by the glass) and room B the cooler room. Option (2) gives room A = 40 °C (warm) and room B = 5 °C (cold).

Question 21

The diagrams below show three circuit arrangements, A, B and C. (A: two cells/batteries connected in parallel branches with a bulb. B: two cells in series in one loop with a bulb. C: two cells in parallel branches with a bulb.) In which of the following arrangements would the bulb light up?

Accepted Answer

B. B only. For the bulb to light, the cells must be connected so current flows in a complete circuit in the same direction. Only arrangement B (cells in series forming one complete loop with the bulb) drives the bulb. The parallel arrangements A and C are not connected so as to push current through the bulb correctly, so only B lights up.

Question 22

Five metal pins A, B, C, D and E were fixed onto a wooden board as shown in diagram 1 below. Diagram 2 shows a circuit connected to wires X and Y. Some of the pins in diagram 1 were connected with wires. Then Wires X and Y were connected to different pairs of pins. The results were recorded in the table below. (X–A,Y–B: No; X–A,Y–C: Yes; X–B,Y–D: No; X–D,Y–E: No.) Which of the following shows the correct arrangement of wires on the circuit card?

Accepted Answer

D. Wires joining A–E and C–E (both A and C to E). The bulb lights only when X–A and Y–C are connected, meaning A and C must be electrically joined. A–B gives no light (A and B not directly joined), B–D no, D–E no. The arrangement in option (4), with A connected to E and C connected to E, makes A and C electrically connected (through E) while leaving the other tested pairs unconnected, matching all results.

Question 23

Clara prepared an experiment set-up with objects P, Q and R. She placed each object near a magnet, an iron nail and a plastic spoon and observe the interaction amongst them. Her observations were recorded in the table below. (P: repel with magnet, attract iron nail, no interaction with plastic spoon. Q: attract with magnet, no interaction with iron nail, no interaction with plastic spoon. R: no interaction with all three.) Based on Clara's observations, which of the following correctly represent objects P, Q and R?

Accepted Answer

C. P: magnet, Q: iron bar, R: copper bar. P repels a magnet — only another magnet can repel a magnet — so P is a magnet (it also attracts the iron nail). Q is attracted by the magnet but does not interact with the iron nail, so Q is a magnetic material, i.e. an iron bar. R has no interaction with anything, so R is a non-magnetic metal, the copper bar. So P = magnet, Q = iron bar, R = copper bar.

Question 24

A rectangular block has surfaces labelled F, G and H as shown in the diagram below. Surface F of the rectangular block was placed in contact with the wooden surface. Then the block was pulled back against the rubber band before it was released and slid across the wooden surface. The experiment was repeated with its two other surfaces, G and H, in contact with the wooden surface. The distance moved by the block was recorded as shown in the table below. (Surface F: area 600 cm², distance 13 cm; G: 1000 cm², 13 cm; H: 1500 cm², 13 cm.) Based on the results of the experiment, which of the following statement(s) is/are true?
A The distance moved by the block is not affected by the size of the contact area.
B The gravitational force acting on the block is the greatest when it moved on surface H.
C There is no frictional force between the block and the wooden surface as the block travelled the same distance.
D Gravitational force and elastic spring force are the only forces acting on the wooden block as the block travelled on the wooden surface.

Accepted Answer

A. A only. The distance moved (13 cm) is the same for all three contact areas, so distance is not affected by the size of the contact area — A is true. B is false (gravitational force depends on the block's mass, which is unchanged). C is false (friction is present and eventually stops the block). D is false (frictional force also acts on the block). So only A.

Question 25

Jason carried out an experiment using a balloon, string and iron straw as shown below. The string was passed through the iron straw and the balloon was then attached firmly to the iron straw with a magnet. When the rubber band on the balloon was removed to release the air, the balloon and the iron straw moved in direction X. Which of the following forces did the iron straw need to overcome when it was moving in direction X?
A Frictional force
B Magnetic force
C Gravitational force

Accepted Answer

A. A only. As the iron straw slides along the horizontal string, it must overcome the frictional force between the straw and the string (A). Magnetic force (B) holds the balloon to the straw and acts vertically/internally, not opposing the horizontal motion; gravitational force (C) acts downward, perpendicular to the horizontal motion, and is balanced by the string. So only frictional force is overcome — A only.

Question 26

In a dark enclosed room, four sheets, P, Q, R and S, were arranged in a straight line as shown below. Sheet P (nearest the candle) has a hole in it. When the candle was lit, a bright circular patch of light was observed only on sheet R. Based on the information above, which of the following statement(s) is/are definitely true?
A Sheet S allowed some light to pass through it.
B Sheets P and R did not allow any light to pass through it.
C Sheet R allowed more light to pass through than sheet Q.

Accepted Answer

B. B only. Light passes through the hole in P and through Q (which must be transparent/have a hole) to reach R, where a bright patch is seen, meaning R is opaque and blocks the light (no light reaches S). So sheets P and R did not allow light through them (P only lets light through its hole; R is opaque) — B is true. A is false (no light reached S). C is false (R blocked light while Q let it through). So B only.

Question 27

William conducted an experiment by heating three rods of identical length made of different metals, P, Q and R, for twenty minutes. He recorded the length of each rod before and after heating. (Before heating all 200 mm; after heating P = 203 mm, Q = 212 mm, R = 208 mm.) William noticed there were gaps between train tracks, and observed that the gap was smaller on a hot day. If metals P, Q and R were used to make the train tracks, which of the following choice of metals would result in the smallest and largest gaps between the tracks on a hot day?

Accepted Answer

B. Smallest gap: Q, Largest gap: P. On heating, the metal that expands the most closes the gap the most, leaving the smallest gap on a hot day. Q expanded most (200→212 mm), so Q gives the smallest gap. P expanded least (200→203 mm), so P gives the largest gap. So smallest gap = Q, largest gap = P.

Question 28

The diagram below shows a girl diving into the water. Position A is standing on the diving board, position B is in the air after jumping, and position C is entering the water. Which of the following shows how the amount of energy changes from A to B to C?

Accepted Answer

D. Potential energy A to B: increases, Kinetic energy B to C: increases. From A to B the girl rises higher (jumps up), so her height and gravitational potential energy increase. From B to C she falls down towards the water, gaining speed, so her kinetic energy increases. So potential energy A→B increases and kinetic energy B→C increases.

P6 Science SA2 2019 — Raffles Girls

Related Sparks

P6 Science SA2 2019 — Raffles Girls

Related papers

Related Sparks