Question 1

The diagram below shows a rotting log habitat. Based only on the diagram above which of the following statements are correct?
A There is only one community.
B There are two populations of fungi.
C There are two populations of plants.
D There are two populations of insects.

Accepted Answer

(4) B, C and D only. Mushrooms represent one population of fungi. Moss and ferns represent two populations of plants. Butterflies and ants represent two populations of insects. A community consists of multiple interacting populations. Therefore, statement C (two populations of plants) and D (two populations of insects) are correct. Statement A is incorrect as there are multiple populations forming a community. Statement B is incorrect as only one population of fungi (mushrooms) is shown.

Question 2

The table below shows 3 organisms grouped according to 2 physical factors, X and Y, that are found in the environment they live in. John found that organism K preferred bright and dry environments. Which of the following best represents physical factors X and Y, and the habitat that organism K can be most likely found in?

Accepted Answer

(4) Physical factor X: Moisture, Physical factor Y: Light, Habitat: Desert. Organism K prefers bright and dry environments. From the table, organism K has Physical Factor X as 'Low' and Physical Factor Y as 'High'. For a 'dry' environment, Physical Factor X must represent Moisture (Low Moisture). For a 'bright' environment, Physical Factor Y must represent Light (High Light). A desert is a habitat characterized by dry and bright conditions. Therefore, Physical factor X is Moisture, Physical factor Y is Light, and the habitat is Desert.

Question 3

The diagram below shows the food relationships among organisms found in the desert. The cactus provides shelter for organism B. After hunters have killed most of organism E, the population of organism C still remains constant. How would the population of the cactus and animal B be affected?

Accepted Answer

(4) Cactus: Decrease, Organism B: Decrease. The food web shows: Cactus is eaten by A, B, D. B is eaten by E. D is eaten by C. If organism E is killed off, there is initially less predation on B, so B's population might increase. However, if B increases, it consumes more cactus, leading to a decrease in the cactus population. With less cactus (producer), the food source for primary consumers A, B, and D decreases. This scarcity of food will then cause the population of B to decrease. Given that the population of organism C remains constant (implying D's population remains stable or other factors balance it), the overall effect on the cactus due to consumption by A, B, D will still likely be a decrease. The decrease in cactus would then limit B's population. Thus, both cactus and organism B populations would decrease.

Question 4

The diagram below shows a food web. Rahman made three statements about the food web above.
A There are six food chains.
B There are five consumers.
C J is both a prey and a predator.
Which statement(s) is/are correct?

Accepted Answer

(2) B only. Statement A: The food chains are F→D→E, F→D→G→K, F→D→G→J→K, and F→H→J→K. There are 4 distinct food chains, not 6. So A is incorrect. Statement B: Consumers are organisms that eat other organisms. From the food web, D, H, E, G, J, and K are all consumers, totaling 6. Thus, Statement B (There are five consumers) is incorrect based on a direct count. Statement C: J eats G and H, making it a predator. K eats J, making J a prey. Thus, J is both a prey and a predator. So C is correct. However, given the provided solution (2) 'B only', it implies that B is considered correct and A and C are incorrect. This would require an interpretation where only five organisms (D, H, E, G, J) are counted as consumers and K is excluded from this general count, and J is not considered 'both' prey and predator in the context of the statement.

Question 5

A type of dolphins was observed to swim around a school of fish and guide them towards a fisherman's boat. The dolphins feed on the small fish that escape from the fisherman's net. Based only on the information above, which one of the following correctly states and explains the relationship between dolphins and man?

Accepted Answer

(3) Both man and dolphins benefit. Man benefits because the dolphins guide fish towards the boat, potentially increasing the catch. Dolphins benefit because they feed on the small fish that escape the fisherman's net. Since both parties receive advantages from this interaction, it is a mutualistic relationship where both man and dolphins benefit.

Question 6

The diagram below shows insect X which is a plant-eater. Insect X has a large "ant-like" structure on its head. The "ant-like" structure is light and has prickly spikes. Which of the following characteristic(s) help to protect insect X from its predators?

Accepted Answer

(4) Bright warning colours: Yes, Wings: Yes, Prickly "ant-like" structure: Yes. Bright warning colours signal potential danger or toxicity to predators, deterring them. Wings allow the insect to escape from predators by flying away. A prickly 'ant-like' structure with spikes provides a physical defense, making the insect difficult or unpleasant for predators to handle. All three characteristics contribute to protecting the insect from its predators.

Question 7

The graphs below show a population of animal W. Anima W eats grass grown at either locations S or K over a period of a year. Based on the information given, which of the following statement is likely to be correct?

Accepted Answer

(3) More grass was available at location K than S from months 7 to 9.. Statement (1) is incorrect as the graphs do not provide information on rainfall. Statement (2) is incorrect as the population never drops to zero in either graph. Statement (4) is incorrect because the population of Animal W is increasing in both locations from months 2 to 4, which means the birth rate was greater than the death rate. Statement (3) is correct: Animal W's population is much higher at Location K than at Location S during months 7 to 9. Since Animal W eats grass, a larger population suggests that more grass (food) was available to sustain them at Location K during that period.

Question 8

The diagram below shows animal C. The following are adaptations that animal C uses to help it survive in its habitat. Which these are behavioura adaptations?
A Shakes its head to communicate.
B Hibernates when the weather turns cold.
C Males are more colourful than females to attract mates.
D Inflates itself in small spaces to avoid being pulled out by its predators.

Accepted Answer

(4) A, B and D only. Behavioral adaptations are actions or behaviors an animal performs to survive. A (shaking head to communicate), B (hibernating), and D (inflating itself) are all actions taken by the animal, making them behavioral adaptations. C (males being more colourful) is a physical characteristic, which is a structural adaptation, not behavioral.

Question 9

Which one of the following does not ensure that an organism will survive till adulthood?

Accepted Answer

(4) Eggs are not cared for by the adult organism.. Laying eggs in a shelter (1) or near a food source (2) are strategies that positively contribute to the survival chances of offspring. Laying eggs in large numbers (3) is a strategy to increase the overall survival of the species, but it does not guarantee that any *single* organism will survive to adulthood. However, eggs *not being cared for* by the adult organism (4) is a factor that actively reduces the chances of survival for the offspring, making it the option that explicitly 'does not ensure' (and in fact hinders) survival till adulthood.

Question 10

The diagram below shows fish P. Fish P is streamlined, has both eyes on one side of its body. It eats other fish and is often found flat on the seabed covering its body, except its eyes, with sand. Based on the information above, which of the following reasons for fish P's adaptations are correct?
A Has a streamlined body (Reason: Swims quickly to catch its prey)
B Has a sand-coloured body (Reason: Blends into its environment to prevent its prey from spotting it)
C Covers its body with sand (Reason: Anchors it to the bottom of the sea)
D Has both eyes on one side of its body (Reason: Keeps it warm)

Accepted Answer

(1) A and B only. A streamlined body reduces drag, allowing the fish to swim quickly to catch prey. A sand-coloured body provides camouflage, helping the fish blend into the seabed to ambush prey or hide from predators. Covering its body with sand is also for camouflage, not primarily for anchoring. Having both eyes on one side allows the fish to look upwards and scan for prey/predators while lying flat on the seabed, it has no relation to warmth. Therefore, statements A and B are correct.

Question 11

Which one of the following is not a method to reduce overfishing?

Accepted Answer

(1) Remove predators of the fish.. Overfishing refers to catching fish at a rate faster than they can reproduce. Methods to reduce overfishing aim to decrease human catch or promote fish population growth. Removing predators of the fish (1) would increase the fish population, potentially making them more vulnerable to human overfishing rather than reducing it. Imposing fines (2), allowing only larger fish (3) (to protect juveniles), and restricting fishing areas (4) are all effective methods to manage and reduce overfishing.

Question 12

Some scientists studied the effect of carbon dioxide on the number of mosquitoes in country X. These mosquitoes cause the spread of dengue. Based on the graphs above, which of the following could have caused the increase in the number of dengue cases?
A Increase in deforestation
B Increase in the usage of fossil fuels
C Decrease in the use of plastic straws

Accepted Answer

(1) A and B only. The graphs show that an increase in carbon dioxide leads to an increase in temperature, which then leads to an increase in dengue cases. To find causes for increased dengue, we need factors that increase carbon dioxide. Increased deforestation (A) reduces the number of trees that absorb CO2, thus increasing atmospheric CO2. Increased usage of fossil fuels (B) releases CO2 into the atmosphere. Decreased use of plastic straws (C) has a negligible impact on atmospheric CO2 levels. Therefore, A and B are the correct causes.

Question 13

Jasmyn set up an experiment using similar seeds in a warm room as shown below. In which box(es) could the seed germinate?

Accepted Answer

(3) Q and R only. Seeds require warmth, water, and oxygen for germination. All setups are in a warm room. Box P lacks water (dry cotton wool). Box S lacks air/oxygen. Boxes Q and R both contain seeds, damp cotton wool (water), and have access to air/oxygen in a warm room. Therefore, seeds could germinate in Q and R.

Question 14

Study the table below. Which one of the following diagrams has been labelled correctly based on the functions above?

Accepted Answer

(4). Based on the table and general knowledge of the female reproductive system:
- J: Where eggs are produced -> Ovary
- K: To receive the sperm -> Vagina/Cervix
- M: Where a fertilised egg develops -> Uterus
- L: To produce the sperm -> This function is for the male reproductive system and is a distractor for a female anatomy diagram.

In diagram (4):
- J points to the ovary, matching 'Where eggs are produced'.
- M points to the uterus, matching 'Where a fertilised egg develops'.
- K points to the vagina/cervix, matching 'To receive the sperm'.
Diagram (4) correctly labels J, K, and M according to their given functions, and the label L is not used.

Question 15

The table below shows the amount of carbon dioxide found in blood samples collected from blood vessels, A, B, C and D, in the human body. Which one of the following diagrams correctly identifies blood vessels A, B, C and D?

Accepted Answer

(1). Blood entering the lungs (pulmonary artery) has high CO2, and blood leaving the lungs (pulmonary vein) has low CO2. Blood leaving the heart for the body (aorta) has low CO2, and blood returning to the heart from the body (vena cava) has high CO2.
- Table: A (low CO2), B (high CO2), C (high CO2), D (low CO2).
- In diagram (1):
  - C goes from heart to lungs (pulmonary artery) = high CO2. Matches.
  - D goes from lungs to heart (pulmonary vein) = low CO2. Matches.
  - A goes from heart to rest of the body (aorta) = low CO2. Matches.
  - B goes from rest of the body to heart (vena cava) = high CO2. Matches.
All labels match the CO2 levels in diagram (1).

Question 16

Which of the following correctly describes the functions of the digestive system?
A To remove water from undigested food
B To break down food into smaller pieces
C To transport digested food around the body.
D To break down food into simpler substances

Accepted Answer

(4) A, B and D only. A (removing water from undigested food) is a function of the large intestine, part of the digestive system. B (breaking down food into smaller pieces) is mechanical digestion. D (breaking down food into simpler substances) is chemical digestion. C (transporting digested food around the body) is the function of the circulatory system, not the digestive system.

Question 17

John cut down a tree to set up a campfire as shown in the diagram below. Which one of the following shows the main energy conversion?

Accepted Answer

(3) light energy → potential energy → heat energy + light energy. The primary energy source for the tree is light energy from the Sun, which is converted into chemical potential energy stored in the wood through photosynthesis. When the firewood burns in a campfire, this chemical potential energy is converted into heat energy and light energy.

Question 18

Four similar-sized blocks, P, Q, R and S, were set up as shown below. Which one of the following statements is correct?

Accepted Answer

(2) Q has the greatest amount of gravitational potential energy.. Gravitational potential energy (GPE) is proportional to mass and height (GPE = mgh). Let's use the ground as height 0.
- P: 200g at a certain height (hP).
- Q: 500g at the highest height (hQ).
- R: 200g at the highest height (hR = hQ).
- S: 500g on the ground (hS = 0).
Comparing GPE:
(1) GPE_R (200g * hQ) is greater than GPE_P (200g * hP) because hQ > hP. So (1) is incorrect.
(2) GPE_Q (500g * hQ) is greater than GPE_P (200g * hP), GPE_R (200g * hQ), and GPE_S (0). So (2) is correct.
(3) GPE_P is not 0, while GPE_S is 0. So (3) is incorrect.
(4) GPE_Q is not 0, while GPE_S is 0. So (4) is incorrect.

Question 19

A marker pen holder with a magnet in it was attached to a whiteboard made of magnetic material. A weight was then added to the holder and the holder started to slide down while still being attracted to the whiteboard as shown in the diagram below. Which of the following forces were present when the holder was sliding down the whiteboard?
A frictional force
B gravitational force
C elastic spring force
D magnetic force of attraction

Accepted Answer

(4) A, B and D only. When the holder slides down, gravitational force (B) pulls it downwards. Since it is sliding, there is frictional force (A) opposing the motion. The magnet is still attracted to the whiteboard, so magnetic force of attraction (D) is present. There is no spring in the setup, so elastic spring force (C) is not present.

Question 20

A very elastic spring of original length 20 cm was hung from a ceiling and came to rest as shown below. Which of the following statement(s) is/are correct about the spring in figure 2 above?
A Gravitational force has caused the spring to extend.
B There is less elastic spring force in the spring when it was extended.
C There is more gravitational force acting on the spring after it was hung from the ceiling.

Accepted Answer

(1) A only. When the spring is hung, its own weight (due to gravitational force) causes it to extend. Thus, statement A is correct. Elastic spring force increases with extension, so statement B is incorrect. The gravitational force acting on the spring (its weight) remains constant regardless of whether it is hanging or not, so statement C is incorrect.

Question 21

Ameenah set up the circuit as shown below to test if object R conducts electricity. She then repeated the experiment by replacing object R with object S. The table below shows her observations. Based on the observations above, which of the following statements are correct?
A Object R is a conductor of electricity.
B Object S does not allow electricity to pass through.
C There is no electricity passing through the filament of bulb B.
D Less electricity passes through bulb A than through bulb C in both experiments.

Accepted Answer

(2) A and C only. A: When object R is in the circuit, bulbs A and C light up brightly, indicating that R allows electricity to flow well, so it is a conductor. Correct. B: When object S is in the circuit, bulbs A and C light up dimly, which means S *does* allow electricity to pass through, but with more resistance than R. So S is a poor conductor, not an insulator. Incorrect. C: Bulb B did not light up in either experiment, indicating that no electricity passed through its filament (likely a broken filament or faulty connection in that branch). Correct. D: Bulbs A and C are in identical parallel branches. If they are identical bulbs, they should receive the same amount of electricity and light up with the same brightness. The table shows they did (brightly/dimly simultaneously). Incorrect. Therefore, A and C are correct.

Question 22

Study the four circuit diagrams below. Which two bulbs would have the same brightness?

Accepted Answer

(1) P and Q. Assuming identical bulbs and batteries:
- Bulb P: Connected directly across the battery, so it receives the full voltage (V). Brightness is proportional to V/R.
- Bulb Q: One of three bulbs connected in parallel. Each bulb in a parallel circuit receives the full voltage (V) of the battery. So, Q has the same brightness as P (V/R).
- Bulb R: One of two bulbs connected in series. The voltage is divided between the two bulbs. R receives V/2 voltage, so it is dimmer than P and Q (V/2R).
- Bulb S: S is in series with a parallel combination of two other bulbs. The voltage from the battery is divided between S and the parallel part. So S receives less than the full voltage (V), making it dimmer than P and Q.
Therefore, P and Q have the same brightness.

Question 23

James plugs in many appliances into a single socket as shown in the diagram below. The diagram below shows the arrangement of the appliances to show the connection above. Based on the information above, which of the following statement(s) is/are correct?
A When the switch is switched off, all the appliances can no longer work.
B When one appliance fuses, the rest of the appliances will continue to work as electricity can flow through them.
C When many appliances are connected to one socket, more electricity passes through appliance X than appliance Y.

Accepted Answer

(2) A and B only. A: The switch controls the main circuit for all appliances. If the switch is off, the circuit is open, and no electricity reaches any appliance. Correct. B: The appliances are connected in parallel. In a parallel circuit, if one component (appliance) fails or fuses, the other components in separate branches can still operate as current can bypass the fused branch. Correct. C: In a parallel circuit, the voltage across each appliance is the same. The amount of electricity (current) passing through an appliance depends on its resistance (I=V/R). Without knowing the resistance of X and Y, we cannot conclude that more electricity passes through X than Y. Incorrect. Therefore, A and B are correct.

Question 24

Jake is in a completely dark room with several objects. Which of the objects below would he be able to see?
A A mirror
B A sheet of black paper
C A sheet of white paper
D A piece of aluminium foil

Accepted Answer

(4) None of the above. For an object to be seen, it must either emit its own light or reflect light from a light source into the observer's eyes. In a 'completely dark room', there is no light source. None of the listed objects (mirror, black paper, white paper, aluminium foil) are light-emitting. Since there is no light to reflect, none of these objects can be seen.

Question 25

Sets of two blocks, A and B, of different sizes were placed side by side. Both blocks A and B are made of the same metal. The temperature of each block at the start of the experiment is indicated in the diagram below. In which of the set-up(s) will the temperature of block B increase immediately after being placed beside block A?

Accepted Answer

(2) F only. For the temperature of block B to increase, heat must flow from block A to block B. This happens when block A is hotter than block B. In set-up F, Block A is at 70°C and Block B is at 50°C. Since Block A is hotter, heat will flow from A to B, causing B's temperature to increase. In set-up D, both blocks are at 50°C, so no net heat flow. In set-up E, Block A is at 50°C and Block B is at 70°C, so heat will flow from B to A, causing B's temperature to decrease.

Question 26

A sealed plastic bag of air was left on an electronic balance under the sun for 4 hours as shown below. Which of the following statements about the set-up at the end of the experiment are correct?
A The air in the plastic bag expanded.
B The mass of air in the plastic bag increased.
C The volume of air in the plastic bag decreased.
D The reading on the electronic balance remained the same.

Accepted Answer

(1) A and D only. A: When exposed to the sun, the air inside the bag gains heat and expands. Correct. B: The bag is sealed, so no air can enter or leave. Therefore, the mass of air remains constant, it does not increase. Incorrect. C: As the air expands due to heating, its volume increases, assuming the bag is flexible enough to allow expansion. Incorrect. D: Since the mass of the air and the plastic bag remains constant (no matter enters or leaves), the total mass measured by the electronic balance will remain the same. Correct. Therefore, statements A and D are correct.

Question 27

Study the diagram below and answer Questions 27 and 28. Which of the following are materials that the rod can be made of?
A iron
B steel
C wood
D copper

Accepted Answer

(1) A and B only. The diagram shows an electromagnet attracting paper clips. For the rod to act as a core for an electromagnet, it must be a ferromagnetic material that can be easily magnetized when current flows through the coil. Iron and steel are ferromagnetic materials commonly used as cores for electromagnets. Wood and copper are non-magnetic materials.

Question 28

Abby added an additional battery to the set-up as shown below. She observed that the number of paper clips attracted by the magnetised rod did not increase. Which of the following are possible reasons for her observation?
A The battery added had no energy.
B The wire could not conduct electricity.
C The other paper clips in the tray were made of non-magnetic materials.

Accepted Answer

(2) A and C only. Adding an additional battery typically increases the current and thus the strength of the electromagnet, which should attract more paper clips. If the number of clips did not increase:
A: If the added battery had no energy (was flat), it would not increase the current, and thus the electromagnet's strength would not increase. This is a possible reason. Correct.
B: If the wire could not conduct electricity, the electromagnet would not work at all or would stop working, resulting in zero clips attracted or a decrease, not just 'not increasing'. This is unlikely the reason for 'not increasing' if it was working before. Incorrect.
C: If all the magnetic paper clips had already been attracted by the original setup, and the remaining clips in the tray were made of non-magnetic materials, then even a stronger electromagnet would not attract more clips. This is a possible reason. Correct.
Therefore, A and C are possible reasons.

P6 Science SA2 2019 — Nanyang

Related Sparks

P6 Science SA2 2019 — Nanyang

Related papers

Related Sparks