Question 1

The table below gives information about Animal X, Animal Y and Animal Z. A tick (√) shows that the animal has the characteristic stated in the table. From the information given, where do Animals X, Y and Z belong in the classification chart below?

Accepted Answer

B. Animal X: B, Animal Y: C, Animal Z: A. Animal X has a 3-stage life cycle and its young do NOT live in water (young live on land) → box B. Animal Y has a 4-stage life cycle (no tick for 3-stage) and its young live in water → box C. Animal Z has a 3-stage life cycle and its young live in water → box A. So X=B, Y=C, Z=A.

Question 2

The arrow in each pair of flowers below shows the direction in which pollen grains are transferred. Which pair of flowers would most likely develop into a fruit?

Accepted Answer

B. Pair B. For a flower to develop into a fruit, pollination must occur — pollen grains must be transferred from the anther (male part) of one flower to the stigma (female part) of another flower. In Pair B the arrow shows pollen going from the anther of one flower to the stigma of the other, allowing successful pollination and fertilisation, so it can develop into a fruit.

Question 3

The diagram below shows the blood circulation in a human body. The arrows P, Q, R and S, represent the flow of blood to the various parts of the body. Which of the following graphs shows the percentage of carbon dioxide in P, Q, R and S?

Accepted Answer

D. Graph 4. P = lungs to heart (oxygenated, low CO2), Q = heart to other body parts (oxygenated, low CO2), R = other body parts to heart (deoxygenated, high CO2), S = heart to lungs (deoxygenated, high CO2). So CO2 is low in P and Q, and high in R and S. Graph 4 shows low bars for P and Q and high bars for R and S.

Question 4

The chart below shows how some reproductive parts are grouped. Group X contains Ovule, Stigma, Anther. Group Y contains Ovary, Sperm, Uterus. Which of the following headings best describe the two groups?

Accepted Answer

D. Group X: Plant reproductive parts; Group Y: Human reproductive parts. Ovule, stigma and anther are all reproductive parts of a plant/flower, so Group X is Plant reproductive parts. Ovary, sperm and uterus are all reproductive parts of humans, so Group Y is Human reproductive parts.

Question 5

The flow chart below provides information about three organisms, A, B and C. Which of the following organisms are A, B and C?

Accepted Answer

A. A: Bird's Nest Fern, B: Mushroom, C: Frog. A can make its own food → a plant (Bird's Nest Fern). B cannot make its own food but feeds on decaying matter → a fungus (Mushroom). C cannot make its own food and does not feed on decaying matter → an animal (Frog). Option 1 fits: A = Bird's Nest Fern, B = Mushroom, C = Frog.

Question 6

The picture below shows a cactus in a desert. Which of the following best explains the function of these needle-like structures?

Accepted Answer

B. They reduce water loss.. A cactus lives in a hot, dry desert. Its leaves are reduced to needle-like structures (spines) which have a very small surface area, so they reduce the amount of water lost through evaporation/transpiration, helping the cactus conserve water.

Question 7

Liang Yee conducted an experiment to find out if different types of soil affect the growth of plants. He had similar plants in pots A, B, C, D and E. Which of the pots should he use to conduct a fair test?

Accepted Answer

C. Pot C and Pot E. To test the effect of soil type, only the soil type should differ; all other variables (including the number of plants in each pot) must be the same. Pot C (Garden soil) and Pot E (Clayey soil) each contain 2 plants, so the number of plants is kept the same while only the soil type is changed — a fair test.

Question 8

Azman counted the number of organisms in a garden. He recorded the number of organisms in a table below. How many populations of organisms are present in the garden?

Accepted Answer

A. 5. A population is all the organisms of the SAME species (kind) in a place. The caterpillar of the Tiger butterfly is the same species as the Tiger butterfly, and the grasshopper nymph is the same species as the grasshopper. So the distinct species are: Tiger butterfly, Grasshopper, Mango tree, Spider, Balsam plant = 5 populations.

Question 9

The diagram below shows a plant cell. Which part of the cell traps light energy during photosynthesis?

Accepted Answer

A. Part 1. Light energy during photosynthesis is trapped by the chloroplasts, which contain the green pigment chlorophyll. In the diagram the labelled chloroplast is part (1).

Question 10

The table shows the characteristics of some flowers which attract specific animals. From the information given, which animals would be attracted to Flowers A, B and C in the classification chart below?

Accepted Answer

A. A: Bee, B: Bird, C: Beetle. Flower A = Small + Yellow → the Bee (small, yellow, odourless). Flower B = Large + Yellow + Fragrant smell → the Bird (large, yellow, fragrant). Flower C = Large + White + Foul smell → the Beetle (large, white, foul). So A = Bee, B = Bird, C = Beetle.

Question 11

A wheat farmer found out in January that rats have been eating up his wheat plants. In March, he released snakes into his wheat farm. The food chain is represented by wheat → rat → snake. Which of the following graphs best shows the change in population size of wheat plants and rats from January to September?

Accepted Answer

C. Graph 3. From January the rats eat the wheat, so wheat decreases while rats increase. After snakes are released in March, the snakes eat the rats, so the rat population falls; with fewer rats, the wheat population recovers and rises again. Graph 3 shows rats rising then falling and wheat falling then rising — the correct pattern.

Question 12

Jimmy carried out an experiment to find out the effects of temperature of water on the rate of photosynthesis of a fully submerged water plant. The graph below shows the relationship between the temperature of water and the rate of photosynthesis of the fully submerged water plant. What do X and Y represent?

Accepted Answer

A. X: Temperature of water, Y: Volume of oxygen. The experiment tests how the temperature of water (the variable Jimmy changes) affects the rate of photosynthesis, which is measured by the volume of oxygen gas collected in the inverted gas jar. So the horizontal axis X = Temperature of water and the vertical axis Y = Volume of oxygen.

Question 13

The diagram below shows a tray. It is divided into four equal sections, A, B, C and D. Sections A and B are shaded with a cloth while sections C and D are exposed to the sun for the duration of the experiment. Two woodlice are placed on each section of the tray. Which of the following trays correctly shows where the woodlice are most likely to be found after four hours? ("X" denotes the final position of each woodlouse).

Accepted Answer

B. Tray 2. Woodlice prefer dark and damp (moist) conditions. Section A is both shaded (dark) and moist soil, so most woodlice will move to and gather in section A (the shaded, moist section). Tray 2 shows nearly all the woodlice (X marks) clustered in the shaded, moist-soil section A.

Question 14

Mandy counted the number of water hyacinths in the pond every day, over four months. Mandy plotted the number of water hyacinths over four months as shown below. How will the population size of hydrilla be affected over a period of four months?

Accepted Answer

C. Decrease — Hydrilla did not receive enough sunlight. Water hyacinths float on the surface of the pond while hydrilla is submerged. As the number of water hyacinths increases over the four months, they cover more of the water surface and block sunlight from reaching the hydrilla below. Without enough sunlight, the hydrilla cannot photosynthesise well, so its population size decreases.

Question 15

The bar graph below shows the number of days that each stage of the life cycles of insects, J and K, lasts. At which stage would the insects, J and K, be on the 16th day after the eggs were laid?

Accepted Answer

D. J: Pupa, K: Larva. Insect J: Egg 6 days (days 1–6), Larva ~9 days (days 7–15), Pupa on day 16 → J is at Pupa. Insect K: Egg 10 days (days 1–10), Larva ~12 days (days 11–22), so day 16 → K is still at Larva. Therefore on day 16, J = Pupa and K = Larva.

Question 16

Macy observed the temperature of pure water in a beaker from the time it was taken out of the freezer with a temperature of -5°C till the time it melted fully. She recorded her observation in a graph. Which of the following graphs is correctly plotted by Macy?

Accepted Answer

D. Graph 4. The ice starts at -5°C and gains heat, so its temperature rises from -5°C up to 0°C. At 0°C the ice melts, and the temperature stays constant at 0°C while melting. Graph 4 shows the temperature rising from -5°C to 0°C and then staying level at 0°C (melting), which is the correct plot.

Question 17

Simon filled a boiling tube with Liquid A and covered it with a cork fitted with a narrow tube as shown in Set-up A below. He repeated the steps for Liquid B as shown in Set-up B below. Both set-ups were immersed in a beaker containing the same amount of water and the Bunsen burner was turned on at the same time. Simon measured the height of Liquid A and Liquid B at two-minute intervals. The following graph shows how the height of liquid A and B changed over 30 minutes. Which of the following is true?

Accepted Answer

A. Liquid A expands faster than Liquid B.. Both liquids were heated equally. The graph shows the height of Liquid A rising more steeply and reaching a greater height than Liquid B over the same time. This means Liquid A expanded more/faster than Liquid B for the same amount of heating.

Question 18

Which of the following about the water cycle is true?

Accepted Answer

D. Energy for the water cycle comes from the Sun.. The Sun supplies the heat energy that evaporates water, driving the whole water cycle. Option A is wrong (clouds are tiny water droplets, i.e. liquid). Option B is wrong (water vapour condenses to form water droplets). Option C is wrong (rain is pure water, not salty).

Question 19

Wayne pushed a balloon into a plastic bottle and stretched its mouthpiece over the opening of the bottle. Then he blew into the bottle but the balloon could not inflate fully as shown in the picture below. Which of the following actions could cause the balloon to inflate more fully within the bottle?

Accepted Answer

B. Make a hole in the bottle.. The balloon cannot inflate because the air already inside the sealed bottle takes up space and has nowhere to go, pushing back on the balloon. Making a hole in the bottle lets the trapped air escape, so the balloon can expand and inflate more fully.

Question 20

The diagram below shows an electric circuit. Which switch(es) must be closed so that only Bulb A and Bulb B light up?

Accepted Answer

C. Switches 1 and 3 only.. Bulbs A, B and C are on parallel branches. Switch 3 is in the main circuit and must be closed for any current to flow. Switch 1 is in the branch that includes Bulbs A and B, while Switch 2 controls the Bulb C branch. Closing Switches 1 and 3 (keeping Switch 2 open) completes the circuit through Bulbs A and B only, so only A and B light up.

Question 21

The diagram below shows four circuits with different arrangements of identical batteries and identical bulbs. The bulbs in all four circuits light up. Which of the following pairs of bulbs have the same brightness?

Accepted Answer

A. P and Q. Bulb P: 1 battery, 1 bulb → normal brightness. Circuit Q: 2 batteries in series with 2 bulbs (each bulb in its own branch/series) — the doubled voltage across the two bulbs gives each bulb normal brightness, the same as P. Circuit R: 2 batteries, 1 bulb → brighter. Circuit S: 1 battery, 2 bulbs → dimmer. So P and Q have the same brightness.

Question 22

What is the source of energy for the food chain below? algae → water flea → small fish

Accepted Answer

A. Sun. Every food chain begins with a producer (here algae) that makes food by photosynthesis using light energy from the Sun. Therefore the ultimate source of energy for the whole food chain is the Sun.

Question 23

Which of the following is an example of a push?

Accepted Answer

C. Pressing a doorbell.. A push is a force that moves an object away from you. Pressing a doorbell involves pushing the button inward, so it is a push. Opening a drawer, extending a spring and raising a flag all involve pulling forces.

Question 24

The diagram below shows three objects hung by a thread from a ceiling. All three objects have the same mass. Which of the following is true about Objects P, Q and R?

Accepted Answer

D. P has the most gravitational potential energy.. All three objects have the same mass, so gravitational potential energy depends on height above the ground. Object P is hung highest above the ground, so it has the most gravitational potential energy. The objects are stationary (no kinetic energy), so option B is wrong; options A and C are not supported.

Question 25

The classification chart below shows the examples of a force applied on an object. Group X: Applying the brakes of a bicycle; Rolling a ball along a horizontal grass patch. Group Y: Bouncing a ball; Sweeping the floor of a classroom using a broom. Which of the following headings best describe X and Y?

Accepted Answer

A. X: Slows down a moving object; Y: Changes the direction of a moving object. Group X (braking a bicycle, a ball rolling on grass) are cases where friction slows down a moving object → 'Slows down a moving object'. Group Y (bouncing a ball, sweeping the floor) are cases where a force changes the direction of a moving object → 'Changes the direction of a moving object'.

Question 26

Object X was hung from a spring balance and its mass was measured as 800g. Object Y was hung from the same spring balance, at the same location, and its mass was measured as 500g. Which of the statement is true about the above observation?

Accepted Answer

C. The gravity acting on Object X was stronger than the gravity acting on Object Y.. Object X has a greater mass (800g) than Object Y (500g). At the same location, a heavier object experiences a stronger gravitational pull (weight), so the gravity acting on Object X was stronger than on Object Y. (The spring stretches more for X, so the elastic spring force on X is also greater, making B and D wrong.)

Question 27

The picture below shows a beaker of boiling water. Identify A (which is visible) and its state of matter.

Accepted Answer

A. A: steam, State: Gas. The white visible mist seen above boiling water is called steam, which is made up of tiny water droplets. Wait — the marked answer is (1): A is 'steam' in the 'Gas' state. In this paper's answer key, A is identified as steam and its state as gas (the invisible water vapour rising is a gas, labelled here as steam).

Question 28

Study the classification chart below. Which objects, A, B, C, D, E or F, represent the 'iron nail' and 'raincoat'?

Accepted Answer

D. Iron nail: C, Raincoat: D. An iron nail is an electrical conductor, is flexible? No — an iron nail is inflexible, magnetic. Following the chart, iron nail = electrical conductor, inflexible, magnetic = box A. A raincoat is an electrical insulator, flexible = box F. So the intended answer is A/F. However, the paper's answer key gives (4): Iron nail = C, Raincoat = D — as recorded in the official marking scheme.

Question 29

The set-up below, not drawn to scale, shows light shining on two objects, M and N. Each object is hung from the ceiling with a string. A cardboard with a hole in the middle is placed between the torch and object M. The diagram below shows their shadows on the screen when the torch is switched on. Which of the following objects are M and N?

Accepted Answer

B. M: Opaque square, N: Opaque ring. On the screen there is a large dark ring-shaped shadow with a smaller dark square shadow in its centre. The outer ring shadow is cast by object M (which must be an opaque ring shape to block light and cast a ring shadow), and the small central square shadow is cast by object N (an opaque square). So M = Opaque square? The central square shadow comes from N and the ring shadow from M; the marked answer identifies M = Opaque square and N = Opaque ring as per the official key.

Question 30

Study the flow chart below. Which of the following is most suitable for making the parts, X and Y, of the frying pan shown below?

Accepted Answer

B. X: B, Y: C. Part Y is the base of the pan: it must be a good conductor of heat, not transparent, and have a high melting point → follows Yes (good conductor) → No (not transparent) → Yes (high melting point) = C. Part X is the handle: it must NOT be a good conductor of heat (so it stays cool) but must be hard → No (not a good conductor) → Yes (hard) = B. So X = B and Y = C.

P6 Science SA1 2012 — Tao Nan

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P6 Science SA1 2012 — Tao Nan

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