Question 1

Which of the following need(s) to be present for bread to turn mouldy?
A  light
B  water
C  oxygen
D  carbon dioxide

Accepted Answer

C. B and C only. Mould (a fungus) needs water and oxygen (plus warmth and food) to grow. Light and carbon dioxide are not required, so only B (water) and C (oxygen) are needed.

Question 2

Mr Song observed the following characteristics of an animal.
A  Number of wings
B  Number of feelers
C  Number of legs it has
D  Number of body parts it has

Which of the above characteristics would conclude that the animal is an insect?

Accepted Answer

B. C and D only. An insect is defined by having 6 legs (C) and 3 body parts — head, thorax and abdomen (D). The number of wings and feelers vary among insects and are not defining, so only C and D conclude it is an insect.

Question 3

The diagram below shows the human digestive system. Which of the following shows the changes in the amount of undigested food at A, B, C and D?

Accepted Answer

C. A decrease, B no change, C decrease, D decrease. A is the mouth where digestion of starch begins (undigested food decreases); B is the oesophagus/gullet where no digestion occurs (no change); C is the stomach where digestion continues (decrease); D is the small intestine where digestion is completed (decrease).

Question 4

The diagram shows a seed growing into a young plant. What is the direction in which food and water are being transported to R?

Accepted Answer

A. food upwards, water upwards. R is the shoot/leaves at the top of the young plant. Water is absorbed by roots and moves upward to R, and food stored in the seed leaf is also transported upward to the growing shoot R. Both move upwards.

Question 5

The diagram below shows the direction of blood flow in some parts of the body. Four blood samples were taken at the same time from four different blood vessels, A, B, C and D, in the body. The graph below shows the amount of oxygen in the four blood samples. Which blood samples shown in the graph were most likely taken from C and D of the circulatory system shown in the diagram above?

Accepted Answer

A. W and X. C carries blood from the heart to the lungs (deoxygenated, low oxygen) and D carries blood from the body to the heart (deoxygenated, low oxygen). Both are low in oxygen, matching the two lowest bars in the graph, W and X.

Question 6

The diagram below represents the transport system of a plant. What do parts F and G and substances D and E represent?

Accepted Answer

D. part F roots, part G leaf, substance D mineral salts, substance E sugar. The water-carrying tube (xylem) carries substance D (water and mineral salts) upward from part F (roots) to part G (leaf). The food-carrying tube (phloem) carries substance E (sugar/food made in the leaf) from part G (leaf) to part F (roots). So F = roots, G = leaf, D = mineral salts, E = sugar.

Question 7

The table below provides some information on four types of cells, A, B, C and D. A tick (✓) indicates the presence of the part of the cell. Which of the above cells is/are most likely to produce oxygen?

Accepted Answer

A. B only. Oxygen is produced during photosynthesis, which requires chloroplasts. From the table only Cell B has chloroplasts, so only Cell B can produce oxygen.

Question 8

Which of the following statements is/are correct of a cockroach and a mealworm beetle?
A  Their young do not have wings.
B  Their young look like the adults.
C  They have four stages in their life cycles.

Accepted Answer

A. A only. Both a cockroach nymph and a mealworm beetle larva do not have wings (A is true of both). B is true only of the cockroach (incomplete metamorphosis), not the beetle. C (four stages) is true only of the mealworm beetle (complete metamorphosis), not the cockroach. So only A applies to both.

Question 9

The diagram below shows the human reproductive systems. Which parts of the reproductive systems produce cells that have to be fused to develop into a baby?

Accepted Answer

A. A and C. Fertilisation requires the fusion of a sperm and an egg. A points to the testis (produces sperm) in the male system and C points to the ovary (produces eggs) in the female system, so A and C produce the cells that fuse.

Question 10

Study the family tree of Timothy below. The family tree shows the members who have attached earlobes or detached earlobes. Which one of the following statements about the family tree is correct?

Accepted Answer

D. Timothy's father has a brother who has attached earlobes.. Reading the pedigree with the key, Timothy's father's side includes a brother shaded as 'male with attached earlobes'. Timothy's parents do not both have attached earlobes, Timothy and his brother are shaded as attached, and the grandfathers are not both detached, so only statement D is correct.

Question 11

Jackie carried out an experiment to find out if the type of water would affect how well fruit that are dispersed by water can float. He planned and carried out an investigation.
Step 1  Collected a lotus fruit and a coconut.
Step 2  Filled a pail with 5 litres of tap water.
Step 3  Filled another identical pail with 5 litres of sea water.
Step 4  Placed the lotus fruit in the first pail and the coconut in the second pail.
Jackie recorded his observations and presented his findings to his teacher who said that he had made a mistake in his investigation. What mistake did Jackie make?

Accepted Answer

A. He used two types of fruit.. To make a fair test of how the type of water affects floating, only the type of water should be changed and the same fruit used. Jackie used two different fruits (lotus fruit and coconut), introducing a second variable, so his mistake was using two types of fruit.

Question 12

Yusoff carried out a project to study more about the habitats of a garden and a desert. Which of the following factors could he use to tell the difference between the habitats of a garden and a desert?
A  type of soil
B  amount of light present
C  amount of water available
D  number of organisms present

Accepted Answer

B. A, B and C only. Physical (non-living) factors that distinguish habitats are the type of soil, amount of light and amount of water. The number of organisms (D) is a result of the habitat, not a physical factor used to tell habitats apart, so A, B and C only.

Question 13

Using the food web provided, answer the question. Which one of the following classifications is correct?

Accepted Answer

B. producer E, prey only A, prey and predator B & D, predator only C. In the food web E is eaten by A and B but eats nothing, so E is the producer. A is eaten (by D/B paths) and only eaten in the prey-only role, B and D are both eaten and eat others (prey and predator), and C is eaten by nothing but eats others, making C the predator only. This matches option B.

Question 14

How many food chains are there in the food web above that involve at least four organisms?

Accepted Answer

D. 4. Tracing chains of four or more organisms from the producer E gives four such chains (e.g. E→A→B→C, E→A→B→D, E→B→... and other valid four-organism paths), so the answer is 4.

Question 15

Which of the following statements about photosynthesis is/are correct?
A  Plants require only light for photosynthesis to take place.
B  During photosynthesis, oxygen is produced by the plants.
C  After photosynthesis, food is stored only in the leaves of a plant.

Accepted Answer

A. B only. Photosynthesis produces oxygen (B is correct). A is wrong because plants also need water, carbon dioxide and chlorophyll, not only light. C is wrong because food can be stored in other parts such as roots, stems and fruits, not only leaves. So only B is correct.

Question 16

Aishah prepared a set-up as shown below and left it in an open field for 24 hours. At every six-hour interval, she took a sample of the water and added liquid A to it. Liquid A changes colour as shown below (amount of carbon dioxide low → yellow; high → red). What colour of water with liquid A would Aishah observe when samples were collected at noon and at midnight respectively?

Accepted Answer

D. At noon yellow, at midnight red. At noon there is bright light, so the water plant photosynthesises and uses up carbon dioxide, making it low → liquid A turns yellow. At midnight there is no light, so no photosynthesis occurs but the plant still respires and releases carbon dioxide, making it high → liquid A turns red.

Question 17

Study the information provided in the classification chart below. Based on the information above, which one of the following represents objects A, B, C and D?

Accepted Answer

D. A copper wire, B iron nail, C towel, D ceramic mug. All objects are opaque (do not allow light to pass). A = conductor + flexible → copper wire; B = conductor + non-flexible → iron nail; C = non-conductor + flexible → towel; D = non-conductor + non-flexible → ceramic mug. This matches option D.

Question 18

Kumala was given a beaker containing three powders, J, K and L, mixed together. These powders cannot be dissolved in water. The properties of the three powders are given in the table below. Which property / properties should Kumala make use of in order to separate the three powders quickly?

Accepted Answer

B. X and Y only. Property Y (magnetism) removes powder L (the only magnetic one). Property X (floating) separates K (floats) from J (sinks). Using X and Y together separates all three powders. Property Z (conducting electricity) cannot be conveniently used to separate solid powders, so X and Y only.

Question 19

Four paper clips, W, X, Y and Z, were fixed onto a cardboard as shown in Diagram 1. Diagram 2 shows a battery and a bulb connected to two wires A and B. Lloyd connected some but not all of the paper clips on the cardboard in Diagram 1 with wires. He then connected A and B across different pairs of paper clips in turn. He recorded his results in the table (W–Y: yes; X–Z: no; Y–X: yes; Z–W: no). Which one of the following shows a possible arrangement of the wires behind the circuit card?

Accepted Answer

D. Wires joining W–Y and Y–X (W connected to Y and Y connected to X). The bulb lights when the pair is connected by a hidden wire. W–Y lights (yes) and Y–X lights (yes), so W, Y and X must all be joined. X–Z (no) and Z–W (no) show Z is not connected to anything. Option D, where W is joined to Y and Y is joined to X (Z isolated), satisfies all four results.

Question 20

The diagram below shows some blue and red bulbs in a circuit. Which switch(es) should be closed in order to light up 2 blue bulbs and 2 red bulbs at the same time?

Accepted Answer

C. S2 and S3 only. Closing S2 and S3 completes the paths that light exactly two blue bulbs and two red bulbs at the same time, while keeping S1's branch open so no extra bulb is bypassed. This is the only combination giving 2 blue + 2 red lit.

Question 21

A cup of water and 2 marbles are placed on a balance scale as shown below. The pointer of the balance is at the centre. Which one of the following is correct?

Accepted Answer

C. The mass of the cup of water is equal to the mass of the two marbles.. A balance compares mass. Since the pointer is at the centre, the two sides are balanced, meaning the mass of the cup of water equals the combined mass of the two marbles. It tells us nothing about their volumes.

Question 22

Which of the following actions are gravity acting on?
A  A pencil rolling on a table
B  A cyclist cycling up a slope
C  A box moving down a ramp
D  A rocket launching into space

Accepted Answer

D. A, B, C and D. Gravity acts on all objects with mass at all times, regardless of how they move. So gravity is acting in all four situations A, B, C and D.

Question 23

Suriah wanted to find out how the rate of evaporation of water was affected by the exposed surface area of water. She poured water into 4 containers, P, Q, R and S, made of the same material. The table below shows the different conditions at the start of the experiment. Which two containers should Suriah compare?

Accepted Answer

C. Q and S. To test only the effect of exposed surface area, all other variables must be the same. Q (temp 25, area 140, volume 300) and S (temp 25, area 50, volume 300) have the same room temperature and same volume of water but different exposed surface areas, so Q and S should be compared.

Question 24

Han Ming conducted an experiment using four bars, A, B, C and D. Each bar was made of a different material. He heated them one at a time over a strong flame for one minute each. The table below shows the temperature of the bars that were recorded before and after the experiment. Which one of the following correctly shows the arrangement of the bars from the best to the poorest conductor of heat?

Accepted Answer

C. C, A, D, B. The temperature rise shows how well each bar conducts heat: A = 50−30 = 20, B = 39−30 = 9, C = 58−30 = 28, D = 43−30 = 13. The larger the rise, the better the conductor. Ordering from largest to smallest rise gives C (28), A (20), D (13), B (9).

Question 25

The diagram below shows the observation made by Chloe when she hung three magnets, F, G and H, next to one another (magnet F = P|Q, magnet G = R|S, magnet H = T|U). Which one of the following correctly shows the observation that would be made by Chloe when magnets F and H are placed next to each other?

Accepted Answer

D. T U P Q joined together in a row (T U | P Q). From the original observation the magnets attract in a chain, so the facing ends are unlike poles. When F and H are brought together, the unlike poles attract and the magnets join in a row as T U P Q (option 4).

Question 26

Which of the following is/are possible conclusion(s) about magnetic force based on Chloe's observation?
A  It acts at a distance.
B  It exerts a push or a pull.
C  It is strongest at the poles of magnets.
D  Its strength is dependent on the material that makes the magnets.

Accepted Answer

B. A and B only. The hanging magnets attract/move without touching, showing the force acts at a distance (A) and exerts a push or a pull (B). The observation does not compare poles strength directly or different materials, so C and D cannot be concluded. Hence A and B only.

Question 27

The table shows the melting and boiling points of two substances, P and R (P: melting point 80 °C, boiling point 150 °C; R: melting point 60 °C, boiling point 250 °C). Which one of the following shows the states of P and R at 70 °C?

Accepted Answer

B. P solid, R liquid. At 70 °C, P is below its melting point of 80 °C so it is still solid. R is above its melting point of 60 °C but below its boiling point of 250 °C, so it is liquid. Hence P solid, R liquid.

Question 28

Rachael made a set-up as shown in the diagram below. It was made up of pipes with openings at A, B, C, D and E. Four mirrors were placed inside the pipes. Rachael used her set-up to see an object X that was placed near one of the openings. Which one of the following would enable Rachael to see object X?

Accepted Answer

A. Position of eye A, position of object X E. Light travels in straight lines and reflects off the mirrors along the pipe paths. Tracing the mirror reflections, light from object X at opening E is reflected through the pipes to reach an eye placed at opening A, so eye at A and object at E is correct.

Question 29

Which one of the following is not an example of energy conversion?

Accepted Answer

B. cooling hot water in a cup. Cooling hot water in a cup is simply heat being transferred from the water to the surroundings, not a conversion from one form of energy to another. Walking up stairs (chemical→kinetic/potential), lighting a candle (chemical→light/heat) and generating electricity (various→electrical) are all energy conversions.

Question 30

The diagram below shows a machine used to drive piles into the ground which serve as support for buildings. As the weight is raised above the ground, it gains gravitational potential energy. When it is released to hit the pile, its gravitational potential energy is converted to kinetic energy. How should distance d and mass of weight be changed in order to increase the kinetic energy of the weight when released?

Accepted Answer

C. distance d increase, mass of weight increase. Gravitational potential energy increases with both height and mass, and it is converted to kinetic energy on release. To increase the kinetic energy, both the distance d the weight is raised and the mass of the weight should be increased.

P6 Science SA2 2016 — Catholic High

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P6 Science SA2 2016 — Catholic High

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