Question 1

The Sun is useful because it ____.
A  provides light for plants to make food
B  produces oxygen for all living things
C  provides heat for all living things

Accepted Answer

B. A and C only. The Sun provides light for plants to make food (photosynthesis) and provides heat for living things, so A and C are correct. Plants, not the Sun, produce oxygen, so B is wrong.

Question 2

The diagram below represents the transfer of energy between organisms in a habitat.

Which 2 letters represent animal-eaters?

Accepted Answer

C. C and D. Energy from the Sun goes to A (producer), then A→B→C→D in a chain, with arrows also feeding into E. A is the producer and B is the plant-eater; C eats B and D eats C, so C and D are the animal-eaters.

Question 3

The diagram below shows two flowers on the same plant.

Which of the above arrow(s) represent(s) pollination?

Accepted Answer

B. A and D only. Pollination is the transfer of pollen grains from the anther to the stigma. Arrows A and D land on the stigma of a flower, so they represent pollination; arrows B and C end elsewhere and do not.

Question 4

The diagram below shows the digestive system of a human body.

Which part(s) shown above does not carry out digestion?

Accepted Answer

C. B, D and F only. B (oesophagus/gullet), D (a non-digesting passage) and F (large intestine/rectum) do not carry out digestion — the oesophagus only transports food and the large intestine mainly absorbs water. The mouth, stomach and small intestine carry out digestion.

Question 5

The picture below shows a plant with thick, fleshy stems.

This plant has adapted to survive best in ____.

Accepted Answer

B. deserts. Thick fleshy stems store water and needle-like leaves reduce water loss — adaptations for a hot, dry environment, so the plant survives best in deserts.

Question 6

The diagram below shows a flower of a plant.

Which of the following birds would most likely feed on the nectar of the above flower?

Accepted Answer

D. Bird with a short, broad, flat beak. Per the marking key the answer is option (4). A bird feeding on nectar deep in a flower needs the most suitable beak shown; option (4) is the correct choice for reaching the flower's nectar.

Question 7

The food web shows the relationships between a producer and organisms A, B, C and D in a community.

The jawbone of one of the organisms is shown below.

Which organism in the above food web is most likely to have such a jawbone?

Accepted Answer

C. C. The jawbone has many sharp, pointed teeth, which are typical of a meat-eater (carnivore). In the food web the carnivore that feeds on other animals is C, so it would have such a jawbone.

Question 8

The diagram below shows a pond community.

How does the presence of the animals benefit the water plants?
A  The water plants are a source of food for the animals.
B  The animals' waste provides nutrients for the water plants.
C  The animals produce carbon dioxide for the water plants to make food.

Accepted Answer

C. B and C only. The animals benefit the plants by their waste providing nutrients (B) and by producing carbon dioxide that the plants use to make food (C). Statement A is a benefit to the animals, not the plants, so the answer is B and C only.

Question 9

Organisms W, X, Y and Z are found in a food chain as shown below.

W → X → Y → Z

If the population of organism Y increases quickly due to abundance of food provided by Man, which one of the following below shows correctly the immediate changes in the populations of organisms X and Z?

Accepted Answer

B. X: decrease, Z: increase. Y eats X, so more Y means more X is eaten and X decreases. Z eats Y, so more Y means more food for Z and Z increases.

Question 10

Musa set up P and Q as shown below using identical type of plants. (Each beaker has a layer of oil and 500 ml of water.)

After a few days, Musa recorded the amount of water left in the beakers and plotted his findings in a graph as shown below.

Which of the following statements about the experiment is correct?

Accepted Answer

B. Plant in set-up P loses more water than plant in set-up Q.. The oil prevents evaporation from the beaker, so water lost equals water taken in by the plant (lost through transpiration). The graph shows set-up P has less water left than set-up Q, so plant P lost (transpired) more water than plant Q.

Question 11

Susan set up an experiment to find out about the conditions needed to slow down the rate of decomposition of a fruit. Three fruits of the same type were placed in each of the flasks A, B, C and D and kept in different conditions as shown below.

Which of the above set-ups A, B, C or D would the fruits be kept fresh for the longest period?

Accepted Answer

D. D. Decomposition is slowed by cold and dry conditions. Set-up D is kept cold (2°C) and contains a substance that absorbs water vapour (dry), so the fruits stay fresh longest.

Question 12

Amelia prepared the set-ups A and B to find out if a certain factor affects the rate of photosynthesis of plant X. She left set-up A in a well-lit room and set-up B in a cardboard box.

Which of the following factors was the changed variable of her experiment?

Accepted Answer

A. presence of light. Set-up A is in a well-lit room and set-up B is in a dark cardboard box, while everything else is the same. The only variable changed is the presence of light.

Question 13

A farmer found a population of harmful insect A on his farm. The length of the life cycle of insect A is one month. The farmer used a certain method at X as shown in the graph and managed to kill all the eggs, young and adults of insect A by the end of two months. The graph below shows the population size of insect A on the farm before and after the method was used.

Which of the following is a likely reason for the increase in the population size of insect A after Month 6?

Accepted Answer

B. Insect A from other places migrated to the farm.. Since the method killed all eggs, young and adults of insect A by the end of two months, there were no surviving insects on the farm to reproduce. So the later increase must come from insect A migrating in from other places.

Question 14

The graph below shows the changes in the number of zebras on a grassland over time.

Based on the graph above, which one of the following is a possible reason for the change in the number of zebras?

Accepted Answer

A. The grassland was partly cleared to build houses from C to D.. From C to D the number of zebras decreases. Clearing the grassland to build houses reduces the zebras' food and habitat, which would cause the population to fall from C to D.

Question 15

The table below shows the characteristics of two plants, A and B. A tick (√) shows the characteristic that each plant has. (Plant A: tick for 'Grows on land'; Plant B: tick for 'Bears fruit'.)

From the information given above, identify the groups that plants A and B belong to in the classification chart below.

Accepted Answer

C. Plant A: Z, Plant B: W. Plant A does not bear fruit (non-flowering) and grows on land (non-aquatic) → group Z. Plant B bears fruit (flowering) and does not grow on land (aquatic) → group W. So A = Z and B = W.

Question 16

Below shows what happens to the leaves of a plant during the day and night respectively. (Leaves are opened during the day and closed during the night.)

Which of the following characteristics of living things is shown above?

Accepted Answer

C. Living things respond to changes.. The leaves open in the day and close at night, reacting to the change between light and dark. This shows that living things respond to changes in their surroundings.

Question 17

Peter wanted to find out if the height of an object affects the depth of the dent made in the sand.

Which two set-ups should he use to conduct a fair test?

Accepted Answer

A. P and Q only. To test if height affects the dent, only the height should differ while the mass stays the same. Set-up P (1 kg, 50 cm) and set-up Q (1 kg, 70 cm) have the same mass but different heights, so they form a fair test.

Question 18

Study the set-up shown below. (Water from a tap drips onto a plastic wheel mounted on a retort stand, turning it.)

Which of the following action(s) would make the wheel spin faster?
A  Increase the water flow of the tap.
B  Increase the distance between the tap and the wheel.
C  Use an iron wheel of similar size instead of a plastic wheel.

Accepted Answer

B. A and B only. Increasing the water flow (A) delivers more force on the wheel, and increasing the distance the water falls (B) makes it hit the wheel faster/harder — both speed up the wheel. Using a heavier iron wheel (C) would be harder to turn, so it would not spin faster.

Question 19

Raju released a marble from point W at the top of a ramp. The marble travelled all the way to the wooden block L and hit it with a soft thud before stopping completely.

Which one of the following statements below is true?

Accepted Answer

D. The marble increases in kinetic energy as it moves from point Y to point Z.. Y is the top of a small hump and Z is lower down, so as the marble rolls down from Y to Z its potential energy is converted to kinetic energy, increasing its kinetic energy. (At W it is stationary so KE is zero; X is lower than Y so X has less PE; on hitting L energy becomes heat and sound, not only heat.)

Question 20

A metal box was moved across the floor as shown in the diagram below. (The box moves to the left; arrows A (left), B (right), C (up) and D (down) are drawn on the box.)

Which of the arrows A, B, C or D, represent the directions of frictional force and gravitational force acting on the box?

Accepted Answer

C. Frictional force: B, Gravitational force: D. Friction always opposes the direction of motion. The box moves left, so friction acts to the right (arrow B). Gravitational force always acts downwards (arrow D).

Question 21

Amanda used the set-up below to study four types of springs, A, B, C and D. She placed objects of different mass on each spring and measured the length of the spring. The results are shown in the graph below.

Using the same set-up, Amanda wanted to compare the mass of two pears below.

Which spring, A, B, C or D, is the most suitable for her set-up?

Accepted Answer

B. B. The pears are light, so a sensitive spring that stretches noticeably for a small mass is needed, while still starting from a short length and staying on the scale. Spring B stretches enough to show a clear difference between the two light pears, making it the most suitable.

Question 22

Which of the following would require a greater force to stop the moving car?

Accepted Answer

D. car travelling at 90 km/h on wet road. A faster car has more kinetic energy and momentum, needing more force to stop. The car at 90 km/h has the greatest speed, and on a wet (slippery) road there is less friction to help it stop, so the greatest force is needed for the 90 km/h car on a wet road.

Question 23

Below are three objects. (Part X is on an umbrella, Part Y is on a scarf, Part Z is on a toothbrush.)

What is a common property Part X, Part Y and Part Z must have in order to work properly?

Accepted Answer

A. Flexible. Per the marking key the answer is option (1), Flexible. The umbrella ribs/canopy, the scarf and the toothbrush bristles all need to be flexible (able to bend) in order to work properly.

Question 24

Sharon was able to arrange four bar magnets as shown below.

Which of the following is another possible arrangement of the above magnets?

Accepted Answer

C. Arrangement 3. For bar magnets to attract and stay joined end to end, unlike poles must face each other. Tracking the labelled ends (A–B, C–D, E–F, G–H) through the original arrangement, only option (3) keeps every joined pair as opposite (attracting) poles, so it is another valid arrangement.

Question 25

Susan shone a torch at a wooden stick forming a shadow as shown in the diagram below.

Which of the following diagrams below shows the correct position of the torch and the shadow of the wooden stick?

Accepted Answer

C. Diagram 3. A shadow forms on the side of the object away from the light source, with the shadow pointing directly away from the torch. Option (3) correctly shows the torch and the shadow cast on the opposite side of the stick.

Question 26

Sheela used the set-ups below to find out more about solids X and Y. She placed each of the solids on the weighing balance as shown in Diagram 1. Then, Sheela placed each of the solids into two containers with the same volume of water. Her results are shown in Diagram 2.

Based on Sheela's observations in the set-ups above, what can she conclude about solids X and Y?
A  Solid X has a smaller mass than Solid Y.
B  Solid X has a greater mass than Solid Y.
C  Solid Y occupied more space than Solid X.

Accepted Answer

D. B and C only. On the balance the X side is lower, so X is heavier — Solid X has a greater mass than Solid Y (B). In the water, Solid Y raises the water level more, so Solid Y occupies more space / has a larger volume than X (C). So B and C only.

Question 27

The diagrams below show four circuits. Which of the circuits will the bulb light up?

Accepted Answer

A. Circuit 1. A bulb lights only when it is part of a complete circuit with the two terminals of the battery connected through the bulb. Option (1) is the circuit where the bulb is correctly connected to both ends of the battery, forming a complete circuit.

Question 28

Cynthia set up the circuit as shown below with rod P and rod Q. Bulb B1 lit up but Bulb B2 did not light up. Cynthia then exchanged the positions of rod P and rod Q. Both bulbs did not light up.

Based on the above results, which of the following is correct?

Accepted Answer

B. Electrical Conductor: P, Fused Bulb: B2. Before swapping, B1 (with rod P) lit, so P is a conductor and B1 works. After swapping, rod P is in the B2 branch but B2 still did not light, so B2 must be fused (a broken bulb). Q is a non-conductor because B1 did not light when Q was in its branch after the swap. So P is the conductor and B2 is the fused bulb.

P6 Science SA1 2018 — Tao Nan

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P6 Science SA1 2018 — Tao Nan

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