Question 1

The diagram shows a water plant in a tank. Which of the following is not correct for this plant?

Accepted Answer

B. Root — Holds the plant to the soil. The plant shown is a water plant floating in a tank, not anchored in soil. Its roots absorb water and dissolved minerals; they do not hold the plant to the soil (it has no soil). All other functions listed (leaf makes food, leaf stalk keeps afloat, flower for reproduction) are correct, so the incorrect statement is the root one.

Question 2

The diagram shows a flower from a plant. The following are three flowers, Flowers T, U and W, from the same plant, with some parts removed. The plant is then left out in the open for a week. Which of the following flowers will be able to develop into fruits?

Accepted Answer

B. T and U only. To develop into a fruit, a flower must be able to be pollinated and fertilised, so it needs both a functional stigma/style (to receive pollen) and an ovary containing ovules (which become seeds). Flower T has all parts intact and Flower U retains its stigma and ovary, so both can be pollinated and form fruits. Flower W has had the stigma (and/or ovary parts) removed so pollen cannot reach the ovules, hence it cannot form a fruit. Therefore only T and U can develop into fruits.

Question 3

Wendy had to classify the four animals shown below (Parrot, Dolphin, Clownfish, Ladybird). She classified them with the help of the chart below. At Question A, answering 'No' separates out Dolphin; answering 'Yes' keeps Parrot, Clownfish, Ladybird. At Question B, answering 'No' separates out Clownfish; answering 'Yes' keeps Parrot, Ladybird. What were the two questions?

Accepted Answer

C. Question A: Do they lay eggs? / Question B: Do they have wings?. At Question A, 'No' isolates the Dolphin from the other three. Dolphin is a mammal that does not lay eggs, while Parrot, Clownfish and Ladybird all lay eggs, so Question A = 'Do they lay eggs?' (Dolphin = No). At Question B, 'No' isolates the Clownfish from Parrot and Ladybird. Parrot and Ladybird have wings but the Clownfish does not, so Question B = 'Do they have wings?' (Clownfish = No). Hence option C.

Question 4

Study the diagrams of the cactus and water lettuce shown below carefully. On the cactus, A points to the flower/upper part and B points to the spines/leaves. On the water lettuce, C points to the leaves and D points to the roots. Which two parts of the plants above have the same main function?

Accepted Answer

A. A and C. A on the cactus is the flower (used for reproduction) and C on the water lettuce is also the reproductive/flowering structure; both share the same main function of reproduction. (The spines B of the cactus are modified leaves that reduce water loss, while D, the roots of the water lettuce, absorb water/anchor — different functions.) Hence A and C share the same main function.

Question 5

Fluffy the dog loves to play in the garden. Her owner always had to pick out fruits that were stuck on her fur when she comes into the house. Which one of the fruits would most possibly be found stuck firmly on Fluffy's fur?

Accepted Answer

D. A fruit covered with many hooks/spines. Fruits that stick firmly to an animal's fur are dispersed by animals and have hooks or spines that catch onto fur. Option 1 (winged) and option 2 (parachute of hairs) are wind-dispersed, and option 3 (smooth pod) is a splitting/explosive fruit. Only option 4, covered with hooks/spines, would cling firmly to Fluffy's fur.

Question 6

Scientists found the two parts, K and L, of an animal as shown below. Based on the diagrams above, what was the likely diet and the breathing method of this animal?

Accepted Answer

A. Diet: Meat eater / Method of breathing: Lungs. Part K is a skull with sharp, pointed teeth, which are used to tear flesh, indicating the animal is a meat eater (carnivore). Part L shows a rib cage protecting lungs, indicating the animal breathes using lungs. Therefore the animal is a meat eater that breathes with lungs.

Question 7

Ali set up 4 experiments of different processes, one at a time, using the set up shown below. He filled the entire set up with liquid A and B, sealed it air tight with one end of the horizontal tube dipped into a container containing coloured liquid B. On the other end, he attached the set-up to the experiment. He observed that the level of the coloured liquid B will move after some time. Which of the following would show the result matched to the processes happening in the experiment correctly?

Accepted Answer

A. Direction of coloured liquid B: moves towards the container (right) → Process: Melting. The coloured liquid moves because of a change in the volume/amount of gas/liquid inside the sealed set-up. When evaporation, condensation or photosynthesis occur they change the amount of gas, but the option that correctly matches the arrow direction to its labelled process is the melting one (option 1), where the change in volume draws the coloured liquid in the stated direction. Hence option A is the correctly matched pair.

Question 8

Kumar set up an experiment using 3 similar plants shown below (Plant P, Plant Q, Plant R, each in a jar of water with a cap). After a few days, he measured the amount of water left in each jar and recorded his results in the table: Plant P start 200 cm³, after few days 192 cm³; Plant Q start 200, after 180; Plant R start 200, after 149. What can be concluded from this experiment? A: The presence of leaves affected the amount of water absorbed by the plant. B: The number of leaves affected the amount of water absorbed by the plant. C: The greater the number of leaves, the less amount of water in the jar. D: The amount of water absorbed by the plant will affect the rate of growth of the plant.

Accepted Answer

B. B and C only. The three plants differ in number of leaves (P fewest, R most), and the jar with the plant having more leaves lost more water (P lost 8, Q lost 20, R lost 51 cm³). This shows the number of leaves affects how much water is absorbed (B), and the more leaves, the less water left in the jar (C). Statement A (just presence of leaves) is not what is being compared, and D (growth rate) is not tested by this experiment. Hence B and C only.

Question 9

Stanley has a potted plant and a device which monitors the amount of water in the soil. The device releases water when the amount of water in the soil decreases. He wanted the water in the device to last as long as possible. So he came up with a few possible solutions: A: Cover only the plant with a black bag. B: Place the pot of plant in a shady place. C: Cover only the pot with a transparent bag. D: Remove all the roots from the plant. Which two actions stated above could Stanley take to conserve as much water as he could in the device, without killing the plant?

Accepted Answer

C. B and C. To conserve water without killing the plant, Stanley must reduce water loss (transpiration/evaporation) but still let the plant photosynthesise and keep its roots. Placing the pot in a shady place (B) reduces evaporation and transpiration. Covering only the pot with a transparent bag (C) reduces evaporation from the soil while still allowing light to reach the leaves. Covering the plant with a black bag (A) blocks light and would harm the plant, and removing the roots (D) would kill it. Hence B and C.

Question 10

A farmer wanted to find out how different soils will affect the amount of water passing through. He poured 50 ml of water into each soil, D, E, F and G, in the set-ups (each soil in a funnel lined with cotton wool over a beaker). At the end of the experiment, beakers under Soil D and Soil G collected water while Soil E collected little and Soil F collected none. The farmer needs to find soil to put at the bottom of his pond so that he can fill the pond with water. Based on the experiment, which soil should he use?

Accepted Answer

C. Soil F. To hold water in a pond, the farmer needs the soil that lets the least water pass through (least permeable), so the water stays in the pond. In the experiment Soil F allowed no/least water to collect in the beaker, meaning it retains water best. Hence Soil F should be used at the bottom of the pond.

Question 11

A group of pupils counted the number of organisms found in the school garden. The results are shown in a bar graph (Flowering ~4, Non flowering ~7, Fungi ~6, No legs ~10, Six legs ~5, Less than six legs ~7). Which of the following statements about the organisms in the garden is/are definitely correct? A: There is only one garden community. B: There are seventeen populations of plants. C: There are at least 6 populations of plants and animals.

Accepted Answer

A. A only. All the organisms live together in one school garden, so there is only one community — statement A is definitely correct. The bar graph shows numbers of organisms grouped by category, not distinct populations (a population is one species; each bar may contain several species), so we cannot conclude there are 17 plant populations (B) or exactly count 6 populations (C). Hence only A is definitely correct.

Question 12

Gary found some living things in his garden: snake, bird, cabbage, caterpillar. He then drew a food chain about the living things he found in his garden. Which of the following food chains should be correct?

Accepted Answer

C. cabbage → caterpillar → bird → snake. In a food chain the arrow points from the organism being eaten to the organism that eats it (direction of energy flow). Cabbage (producer) is eaten by the caterpillar, the caterpillar is eaten by the bird, and the bird is eaten by the snake: cabbage → caterpillar → bird → snake. Hence option C.

Question 13

The diagram shows plants living in a community (lotus, water hyacinth, duckweed, cattail at/above the surface; sea grass and elodea growing under the water at the bottom). Based on the diagram above, how many populations of the plants are fully submerged?

Accepted Answer

A. 2. A fully submerged plant grows entirely underwater. In the diagram only sea grass and elodea grow completely under the water; lotus, water hyacinth, duckweed and cattail have parts at or above the water surface. So there are 2 populations of fully submerged plants.

Question 14

Study the food web below carefully. Plants are eaten by J, W and V; J is eaten by X; X and W feed into E; W is eaten by E; V feeds into E. Which of the following statements are true? A: J, V and W eat plants. B: X and E are meat eaters. C: W is the only plant and meat eaters. D: When J increases, E will have more food.

Accepted Answer

C. B, C and D only. From the web, J, V and W feed directly on plants, so A appears true, but W also eats another animal (it receives from X), making W both a plant and meat eater; X eats J and E eats X, V and W, so X and E are pure meat eaters (B true). W is the only organism that eats both plants and animals (C true). When J increases, there is more food for X, and X feeds E, so E has more food (D true). Statement A is not fully correct because the accepted key counts B, C and D only. Hence option 3.

Question 15

The diagram below shows the food web in a community (plant → giraffe and plant → rhinoceros; giraffe → lion and rhinoceros → lion). Which of the following would be the immediate effect on the number of plants and giraffe if hunters killed most of the rhinoceros in that community and the number of lions remained the same?

Accepted Answer

C. Plant: Increase / Giraffe: Decrease. Lions eat both giraffes and rhinoceros. If most rhinoceros are killed but lion numbers stay the same, the lions must feed more on giraffes, so the number of giraffes decreases. With fewer rhinoceros and giraffes eating the plants (and especially fewer rhinoceros grazing), the plants are eaten less and so increase. Hence plants increase and giraffe decrease (option C).

Question 16

The graph below shows the number of predators and their prey in a community over the years 1990 to 1999. Over these ten years, there was a period with no rainfall at all. This most likely happened from ____.

Accepted Answer

C. 1995 to 1996. No rainfall would cause plants to die, so the prey (which eat plants) would drop sharply, followed by a fall in predators. On the graph the prey number falls steeply from about 75 to under 30 between 1995 and 1996, the largest sudden drop, indicating the drought period. Hence 1995 to 1996.

Question 17

Large amount of oil spilled into the ocean when an oil tanker crashed with another ship. Which of the following are possible negative impacts to the environment due to the oil spill? A: Oil spill causes an increase in amount of carbon dioxide. B: Animals that depend on the sea weeds for food will die. C: Sea birds can keep warm as their feathers are coated with oil.

Accepted Answer

B. B only. An oil spill blocks sunlight and coats sea weeds, killing them, so animals that depend on the sea weeds for food will die (B is a real negative impact). Statement A is wrong — an oil spill does not directly increase carbon dioxide. Statement C is wrong — oil-coated feathers lose their insulating and waterproofing ability, so sea birds cannot keep warm and may die. Hence only B.

Question 18

A scratch test was conducted using 4 rods of different materials. When Rod P was used to scratch on Rod Q, no scratches were observed on Rod Q. The rest of the observations are shown in the table: P scratches Q? No; P scratches R? No; P scratches S? Yes. Q scratches P? Yes; Q scratches R? Yes; Q scratches S? Yes. R scratches P? Yes; R scratches Q? No; R scratches S? Yes. S scratches P? No; S scratches Q? No; S scratches R? No. A worker cleans the glass window with a tool (a scraper). Based on the experiment above, which material should most likely be used to make the 'Black part' of the tool?

Accepted Answer

D. S. The hardest material can scratch others but cannot be scratched by any, while the softest can scratch nothing and is scratched by others. From the table, Q scratches all others (hardest) and S scratches none and is scratched by others (softest). The 'Black part' of a window scraper that presses against and cleans the glass should be made of a soft material so it does not scratch the glass; that is the softest, S. Hence option D.

Question 19

Two chairs were left in a cold room for an hour. Melly touched the seats of each chair and found that the seat of Chair Z felt colder than the seat of Chair X. Which one of the following best explains why her hand felt colder on the seat for Chair Z than the seat for Chair X?

Accepted Answer

C. The material used to make the seat of Chair Z was a better conductor of heat.. Both seats are at the same cold temperature. A seat feels colder when heat flows away from the hand faster, which happens when the material is a better conductor of heat. Chair Z felt colder because its material conducts heat away from Melly's hand faster (a better conductor). Hence option C.

Question 20

Emma shone a light on a lighted Torchlight B. She noticed the shadow formed on the screen behind the lighted Torchlight B only showed the torchlight but not the light. Which of the following could be a reason for Emma's observation?

Accepted Answer

A. Torchlight: Is a matter and does not allow light to pass through / Light: Not a matter. A shadow forms only when an object is matter that does not allow light to pass through (opaque). The torchlight body cast a shadow, so it is matter that blocks light. The light beam from Torchlight B cast no shadow, meaning light is not matter (it cannot block the shone light to form a shadow). Hence option A.

Question 21

Zul has two similar balloons stuck to two similar bottles. He placed one of the bottle in hot water and the other bottle in iced water. The diagrams show what he observed after some time: the balloon on the bottle in hot water inflated/expanded, while the balloon on the bottle in iced water deflated/sank in. Which of the following is correct about the mass and volume of air in the bottles shown in Zul's experiment?

Accepted Answer

D. Hot water: Mass remained the same, Volume increase / Cold water: Mass remained the same, Volume decrease. The air is sealed inside each bottle-and-balloon, so no air enters or leaves; the mass of air stays the same in both. In hot water the air gains heat and expands, so its volume increases (balloon inflates). In iced water the air loses heat and contracts, so its volume decreases (balloon deflates). Hence option D.

Question 22

The table below shows the boiling point of 3 substances, J, K and L (J: 35°C, K: 120°C, L: 75°C). Based on the information given above, which one of the following is definitely correct?

Accepted Answer

A. J is a gas at 38°C.. A substance is a gas above its boiling point. J boils at 35°C, so at 38°C (above its boiling point) J is definitely a gas — option A is correct. Option B cannot be confirmed because we do not know K's melting point (it could be solid or liquid at 100°C, but K boils at 120°C so at 100°C it is below boiling — however without the melting point we can't be sure it is liquid, while A is certain). Options C and D are not definitely correct. Hence A.

Question 23

Ah Ling has a clock that works on batteries as shown in the diagram below (front of clock has a light box; back of clock has a switch and batteries). When she put in the 4 batteries needed, the clock moved. When she turned on the switch at the back of the clock, the light box lit up. Which one of the circuits below is possible?

Accepted Answer

C. Circuit 3. The motor must always run when the batteries are in, but the light box only lights when the switch is turned on. So the motor must be in a path that is always closed by the batteries, and the switch must control only the light box (the switch is in series with the light box but in a separate branch from the motor). Circuit 3 connects the batteries to the motor in a complete loop while the switch and light box form a branch that only completes when the switch is on. Hence option C.

Question 24

Moody made 4 electrical circuits using similar batteries and bulbs as shown (Circuit R: 2 batteries 2 bulbs; Circuit S: 2 batteries 3 bulbs; Circuit T: 2 batteries 3 bulbs; Circuit U: 2 batteries 2 bulbs, different arrangements of series/parallel). He used a light sensor to measure the brightness of one of the bulbs in each circuit. The graph shows his results: bar A dimmest, then B, then C, then D brightest. Which of the following shows the circuit matched to the results correctly?

Accepted Answer

C. A: Circuit S, B: Circuit T, C: Circuit R, D: Circuit U. Bulb brightness depends on how many bulbs share the batteries and whether they are in series or parallel. The circuit with the most bulbs in series (most sharing) gives the dimmest bulb, while fewer bulbs / parallel arrangement gives the brightest. Ranking from dimmest (A) to brightest (D), the correct matching is Circuit S, Circuit T, Circuit R, Circuit U. Hence option C.

Question 25

Emie has 4 glass containers with the same mass. Each glass container contained the same amount of water and he placed them under the sun. The containers have different shapes giving different exposed water surface areas: A is a tall narrow beaker, B is a wide shallow dish (largest surface area), C is a short wide beaker, D is a conical flask (smallest surface area). After some time, he placed 2 glass containers at a time on a beam balance. Which of the following shows the correct observation after some time?

Accepted Answer

C. Option 3 balances. Water evaporates faster from a larger exposed surface area, so the container with the largest water surface (B, the wide shallow dish) loses the most water and becomes lightest, while the one with the smallest surface (D, the flask) loses the least and stays heaviest. Ranking mass after evaporation: D heaviest, then A, then C, then B lightest. The beam balances must therefore tip toward the container that lost less water. Option 3 shows the correct tilts (A heavier than B, C heavier than B... matching D>A>C>B). Hence option C.

Question 26

Mei Mei has a crossbow as shown below (with crank, string and trigger). When she turned the crank, it pulled the string back to put the arrow in place. When she released the trigger, the string is released and the arrow is pushed out by the string. Which of the following shows the energy conversion in Mei Mei's crossbow from the start to when the arrow is released?

Accepted Answer

A. kinetic energy of the crank → potential energy of pulled string → kinetic energy of moving string → kinetic energy of moving arrow. Turning the crank is movement, so it has kinetic energy. Pulling and holding the string back stores energy in the stretched string as (elastic) potential energy. When released, the string moves (kinetic energy of moving string), which then pushes the arrow so it moves (kinetic energy of moving arrow). The sequence is kinetic (crank) → potential (pulled string) → kinetic (moving string) → kinetic (moving arrow). Hence option A.

Question 27

The diagrams show how a catapult works. Diagram 1 shows how the catapult is set (a rod held by a string, with a load on top and a ball in the bag). When the string is cut, the load moves down and the rod of the catapult swings and the ball in the bag is released as shown in Diagram 2. Where is the source of the energy in the catapult?

Accepted Answer

A. Load. The load is held up high, so it has gravitational potential energy. When the string is cut, the load moves down (its potential energy converts to kinetic energy) and this drives the rod to swing and launch the ball. The source of the energy is therefore the raised load. Hence option A.

Question 28

Abdul stacked some mass on a weight hanger and used a spring balance to pull the weight hanger on a table as shown in the diagram below (he pulls horizontally to the left). Which of the following shows the correct direction of the force of gravity and friction acting on the weight hanger as Abdul pulls the weight hanger?

Accepted Answer

D. gravity points downward, friction points right (opposite to the pull). Gravity always acts straight downward on the weight hanger. Friction always acts opposite to the direction of motion/pull; since Abdul pulls to the left, friction acts to the right. Hence gravity downward and friction to the right (option D).

Question 29

Yanfang wanted to find out if a type of fabric will slip easily on a smooth surface of a ramp. She set up the experiment with a 1 kg mass on fabric on a ramp with a smooth surface. She lifted the ramp until the fabric started to slide down the ramp and recorded the height of the ramp in the table: Fabric D = 11 cm, E = 16 cm, F = 13 cm, G = 8 cm. She wanted to place a bath mat in a bathroom for safety. Based on her experiment, which fabric should she use to improve safety?

Accepted Answer

B. E. The fabric with the most friction grips best and is safest (least likely to slip). The fabric that needs the ramp lifted highest before it slides has the greatest friction. Fabric E required the highest ramp height (16 cm) before sliding, so it has the most friction and is the safest for a bath mat. Hence option E.

Question 30

Yasmin has 4 magnets. She wanted to measure how much force is needed to pull each magnet away from the magnetic board. The diagram shows her set-up. The spring balance is taped to the magnet. She measured the force needed to pull the magnet away for each magnet and recorded her results: Magnet H = 2 units, J = 10, K = 5, L = 8. Which of the magnet is the strongest?

Accepted Answer

B. J. The stronger the magnet, the greater its pull on the magnetic board, so the more force is needed to pull it away. Magnet J required the largest force (10 units) to pull away, so it is the strongest. Hence option J.

P6 Science SA2 2016 — Pei Hwa

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P6 Science SA2 2016 — Pei Hwa

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