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Primary 6 PSLE Science Practice Paper 3
Free P6 PSLE Science Practice Paper 3, Nemo3 AI version, with questions, answers, and PSLE-focused practice for Singapore students.
These static practice materials are generated from the site's syllabus and paper-generation workflow, with source and model context shown so students and parents can evaluate the material before use.
Questions
TuitionGoWhere Practice Paper - Science Primary 6 PSLE
TuitionGoWhere Practice Paper (AI) — Version 3
Subject: Science
Level: Primary 6 PSLE
Paper: Practice Paper (Full)
Duration: 1 h 45 min
Total Marks: 100
Name: ________________________
Class: ________________________
Date: ________________________
Instructions to Candidates
- Do not open this booklet until you are told to do so.
- Follow all instructions carefully.
- Answer all questions.
- For Section A, shade your answers on the Optical Answer Sheet (OAS) provided.
- For Section B, write your answers in the spaces provided in this booklet.
- The number of marks is given in brackets [ ] at the end of each question or part question.
- The total marks for this paper is 100.
Section A: Multiple-Choice Questions (56 marks)
Questions 1 to 28 carry 2 marks each. For each question, four options are given. Choose the correct answer and shade the corresponding oval (1, 2, 3 or 4) on the OAS.
1. The diagram below shows a food web in a forest ecosystem.
Generated diagram for Q1.
Which of the following statements about the food web is correct?
(1) The grasshopper is both a prey and a predator. (2) The hawk is a primary consumer. (3) The snake has only one food source. (4) The rabbit is a decomposer.
2. The table below shows the characteristics of four organisms, P, Q, R, and S.
| Organism | Makes its own food | Reproduces by spores | Has chlorophyll |
|---|---|---|---|
| P | Yes | No | Yes |
| Q | No | Yes | No |
| R | Yes | No | Yes |
| S | No | No | No |
Which organism is most likely a fungus?
(1) P
(2) Q
(3) R
(4) S
3. Study the classification chart below.
Generated diagram for Q3.
Which of the following organisms is classified incorrectly if placed under "Non-Flowering Plants"?
(1) Fern
(2) Moss
(3) Mushroom
(4) Conifer
4. The diagram below shows a cell.
Generated diagram for Q4.
Which part of the cell controls all activities in the cell?
(1) Cell wall
(2) Cytoplasm
(3) Nucleus
(4) Vacuole
5. Four students made the following statements about microorganisms.
| Student | Statement |
|---|---|
| Ali | All microorganisms are harmful. |
| Bala | Bacteria can only be seen under a microscope. |
| Cindy | Yeast is a type of bacteria. |
| Devi | Mould reproduces by seeds. |
Which student made a correct statement?
(1) Ali
(2) Bala
(3) Cindy
(4) Devi
6. The diagram below shows the life cycle of a mosquito.
Generated diagram for Q6.
At which stage does the mosquito not feed?
(1) Egg
(2) Larva
(3) Pupa
(4) Adult
7. The table below shows the properties of four materials, A, B, C, and D.
| Material | Flexible | Waterproof | Transparent | Conducts electricity |
|---|---|---|---|---|
| A | Yes | Yes | No | No |
| B | No | Yes | Yes | No |
| C | Yes | No | No | Yes |
| D | No | Yes | No | Yes |
Which material is most suitable for making electrical wires?
(1) A
(2) B
(3) C
(4) D
8. Study the flowchart below.
Generated diagram for Q8.
Which of the following describes the state of matter of oxygen at room temperature?
(1) Solid
(2) Liquid
(3) Gas
(4) Cannot be determined
9. The diagram below shows a magnet being brought near a steel paper clip.
Generated diagram for Q9.
Which of the following explains why the steel paper clip is attracted to the magnet?
(1) The paper clip becomes a temporary magnet with opposite polarity at the near end. (2) The paper clip becomes a permanent magnet. (3) The magnet loses its magnetism. (4) The paper clip is made of a non-magnetic material.
10. Four objects, W, X, Y, and Z, are placed in water. The diagram below shows their positions.
Generated diagram for Q10.
Which object has the greatest density?
(1) W
(2) X
(3) Y
(4) Z
11. The diagram below shows a simple circuit.
Generated diagram for Q11.
When the switch is closed, what will happen to the brightness of the two bulbs?
(1) Both bulbs will light up with equal brightness. (2) B1 will be brighter than B2. (3) B2 will be brighter than B1. (4) Neither bulb will light up.
12. The graph below shows the temperature of a substance as it is heated over time.
Generated graph for Q12.
At which stage(s) is the substance undergoing a change of state?
(1) 0 to 10 minutes only
(2) 10 to 15 minutes only
(3) 0 to 10 minutes and 10 to 15 minutes
(4) 15 minutes onwards only
13. The diagram below shows the water cycle.
Generated diagram for Q13.
Which process in the water cycle involves a change of state from gas to liquid?
(1) Evaporation
(2) Condensation
(3) Precipitation
(4) Collection
14. A plant is placed in a dark cupboard for 48 hours. After that, a leaf is tested for starch using iodine solution. What will be the observation?
(1) The leaf turns blue-black. (2) The leaf turns yellow-brown. (3) The leaf turns orange. (4) The leaf remains green.
15. The diagram below shows a cross-section of a leaf.
Generated diagram for Q15.
Which part of the leaf is mainly responsible for gaseous exchange?
(1) Upper epidermis
(2) Palisade mesophyll
(3) Stomata
(4) Xylem
16. The diagram below shows the human respiratory system.
Generated diagram for Q16.
Where does gaseous exchange take place in the respiratory system?
(1) Trachea
(2) Bronchi
(3) Alveoli
(4) Nasal cavity
17. The diagram below shows a food chain.
Generated diagram for Q17.
If the grass captures 10,000 J of energy from the Sun, approximately how much energy is transferred to the snake?
(1) 10 J
(2) 100 J
(3) 1,000 J
(4) 10,000 J
18. Which of the following is an example of a structural adaptation?
(1) A bird migrating south for winter. (2) A chameleon changing its skin colour. (3) A cactus having thick, fleshy stems. (4) A bear hibernating in winter.
19. The diagram below shows a simple pulley system.
Generated diagram for Q19.
If a load of 50 N is lifted using a fixed pulley, what is the minimum effort needed to lift the load? (Ignore friction and weight of pulley/rope.)
(1) 25 N
(2) 50 N
(3) 75 N
(4) 100 N
20. A spring is stretched by hanging different weights on it. The table below shows the results.
| Weight (N) | Length of spring (cm) |
|---|---|
| 0 | 10 |
| 2 | 14 |
| 4 | 18 |
| 6 | 22 |
What is the length of the spring when a weight of 8 N is hung on it?
(1) 24 cm
(2) 26 cm
(3) 28 cm
(4) 30 cm
21. The diagram below shows a ray of light hitting a plane mirror.
Generated diagram for Q21.
What is the angle of reflection?
(1) 30°
(2) 60°
(3) 90°
(4) 120°
22. Which of the following shows the correct order of energy conversion when a battery-powered torch is switched on?
(1) Chemical energy → Electrical energy → Light energy + Heat energy (2) Electrical energy → Chemical energy → Light energy + Heat energy (3) Light energy → Electrical energy → Chemical energy + Heat energy (4) Heat energy → Chemical energy → Electrical energy → Light energy
23. The diagram below shows a lever system.
Generated diagram for Q23.
What is the minimum effort needed to balance the load? (Ignore weight of lever.)
(1) 10 N
(2) 20 N
(3) 40 N
(4) 80 N
24. Four beakers contain equal volumes of water at different temperatures. Identical sugar cubes are dropped into each beaker at the same time. In which beaker will the sugar dissolve the fastest?
(1) Water at 10°C
(2) Water at 30°C
(3) Water at 50°C
(4) Water at 80°C
25. The diagram below shows the reproductive parts of a flowering plant.
Generated diagram for Q25.
Where are the male gametes produced?
(1) Stigma
(2) Ovule
(3) Anther
(4) Ovary
26. Which of the following statements about forces is correct?
(1) A force can only be exerted by living things. (2) Friction always acts in the same direction as motion. (3) Gravitational force acts on all objects with mass. (4) Magnetic force can only act through air.
27. The diagram below shows a circuit with three identical bulbs.
Generated diagram for Q27.
If bulb B2 fuses (blows), what happens to the brightness of bulbs B1 and B3?
| B1 | B3 | |
|---|---|---|
| (1) | Brighter | Brighter |
| (2) | Brighter | Dimmer |
| (3) | Dimmer | Same |
| (4) | Dimmer | Brighter |
28. The graph below shows the population of prey and predator in an ecosystem over time.
Generated graph for Q28.
Which statement best explains the pattern shown?
(1) The predator population increases when the prey population decreases. (2) The prey population increases when the predator population increases. (3) The predator population increases after the prey population increases. (4) The prey and predator populations are not related.
Section B: Open-Ended Questions (44 marks)
Write your answers in the spaces provided. The number of marks is given in brackets [ ] at the end of each question or part question.
29. The diagram below shows a plant cell and an animal cell.
Generated diagram for Q29.
(a) Identify two structures present in the plant cell but absent in the animal cell. [2]
(b) State the function of the chloroplast. [1]
(c) Explain why plant cells have a large vacuole while animal cells have small vacuoles. [2]
30. The diagram below shows the life cycle of a flowering plant.
Generated diagram for Q30.
(a) Name the process that occurs between pollination and fruit formation. [1]
(b) Describe how the process in (a) takes place. [2]
(c) State two ways in which seeds can be dispersed. [2]
31. The diagram below shows a food web in a pond ecosystem.
Generated diagram for Q31.
(a) Identify all the primary consumers in the food web. [1]
(b) If all the zooplankton are removed from the pond, explain how the population of small fish would be affected. [2]
(c) State the role of decomposers in the ecosystem. [1]
32. The diagram below shows an experiment to investigate the conditions needed for photosynthesis.
Generated experimental_setup for Q32.
(a) Which setup(s) serve as the control(s) for this experiment? Explain your answer. [2]
(b) In which setup(s) will the leaf turn blue-black when tested with iodine? [1]
(c) What is the purpose of destarching the plants before the experiment? [1]
33. The diagram below shows a simple electrical circuit with a battery, a switch, and three identical bulbs arranged in parallel.
Generated diagram for Q33.
(a) State one advantage of connecting bulbs in parallel compared to in series. [1]
(b) If bulb B1 is removed from its holder, what happens to the brightness of bulbs B2 and B3? Explain your answer. [2]
(c) The battery supplies a voltage of 6 V. What is the voltage across each bulb? [1]
34. The diagram below shows a lever system used to lift a rock.
Generated diagram for Q34.
(a) Calculate the minimum effort needed to lift the rock. [2]
(b) State the principle of moments used in your calculation. [1]
(c) If the effort is applied at an angle of 30° to the lever arm instead of perpendicular, how would the required effort change? Explain. [1]
35. The diagram below shows the water cycle.
Generated diagram for Q35.
(a) Name the process by which water vapour changes into water droplets to form clouds. [1]
(b) Explain how plants contribute to the water cycle. [2]
(c) State one human activity that can disrupt the water cycle and explain its effect. [2]
36. The diagram below shows a magnet being used to separate a mixture of iron filings and sulfur powder.
Generated experimental_setup for Q36.
(a) Explain why the iron filings are attracted to the magnet but the sulfur powder is not. [2]
(b) After separation, the iron filings are heated strongly with sulfur powder in a test tube. A new compound is formed. Name this compound. [1]
(c) State one property of the new compound that is different from the original mixture. [1]
37. The diagram below shows the human digestive system.
Generated diagram for Q37.
(a) In which organ does most of the digestion of food take place? [1]
(b) State the function of the small intestine. [1]
(c) Explain what happens to undigested food in the large intestine. [2]
38. The diagram below shows a ray of light passing through a rectangular glass block.
Generated diagram for Q38.
(a) State what happens to the speed of light when it enters the glass block from air. [1]
(b) Explain why the emergent ray is parallel to the incident ray. [2]
(c) If the angle of incidence is increased to 60°, how will the lateral displacement change? [1]
39. The table below shows the melting and boiling points of four substances.
| Substance | Melting point (°C) | Boiling point (°C) |
|---|---|---|
| A | -114 | 78 |
| B | 0 | 100 |
| C | 801 | 1413 |
| D | -219 | -183 |
(a) Which substance is a liquid at room temperature (25°C)? [1]
(b) Which substance is a gas at room temperature? [1]
(c) Substance C is sodium chloride. Explain why it has such high melting and boiling points. [2]
40. The diagram below shows a food pyramid for a grassland ecosystem.
Generated diagram for Q40.
(a) Explain why the number of organisms decreases at each higher trophic level. [2]
(b) If a disease kills most of the grasshoppers, predict what will happen to the populations of frogs and hawks. Explain your answer. [2]
(c) State one difference between a pyramid of numbers and a pyramid of biomass. [1]
41. The diagram below shows an experiment to investigate the effect of light intensity on the rate of photosynthesis.
Generated experimental_setup for Q41.
(a) State the relationship between light intensity and the rate of photosynthesis. [1]
(b) Explain why the rate of photosynthesis decreases as the lamp is moved further away. [2]
(c) Suggest one other factor that could limit the rate of photosynthesis even if light intensity is high. [1]
42. The diagram below shows a circuit with a battery, a variable resistor, a fixed resistor, an ammeter, and a voltmeter.
Generated diagram for Q42.
(a) What is the purpose of the variable resistor in this circuit? [1]
(b) If the resistance of the variable resistor is increased, what happens to the ammeter reading? Explain. [2]
(c) The voltmeter reads 3 V across the fixed resistor when the current is 0.5 A. Calculate the resistance of the fixed resistor. [2]
43. The diagram below shows the life cycle of a butterfly.
Generated diagram for Q43.
(a) Name the type of metamorphosis shown by the butterfly. [1]
(b) State one difference between the larva and the adult in terms of feeding habits. [1]
(c) Explain why the pupa stage is important in the life cycle. [2]
44. The diagram below shows a simple electromagnet.
Generated experimental_setup for Q44.
(a) State two ways to increase the strength of the electromagnet. [2]
(b) Explain why the paper clips are attracted only when the switch is closed. [2]
(c) What happens to the magnetism of the iron nail when the switch is opened? [1]
45. The diagram below shows a classification key for some animals.
Generated diagram for Q45.
(a) Using the key, identify the group for an animal that has a backbone, no feathers, has hair, and lives on land. [1]
(b) State one limitation of using a dichotomous key for classification. [1]
(c) An animal has a backbone, no feathers, no hair, and lives in water. Could it be a whale? Explain. [2]
46. The diagram below shows a solar panel system powering a house.
Generated diagram for Q46.
(a) State the main energy conversion that takes place in the solar panels. [1]
(b) Explain why an inverter is needed in this system. [2]
(c) State one advantage and one disadvantage of using solar energy. [2]
47. The diagram below shows a beaker of water being heated.
Generated diagram for Q47.
(a) Name the process by which heat is transferred through the water. [1]
(b) Explain how this process transfers heat throughout the water. [2]
(c) Why does this process not occur in solids? [1]
48. The diagram below shows a seedling growing in a pot placed near a window.
Generated diagram for Q48.
(a) Name the response of the plant to light shown in the diagram. [1]
(b) Explain how the plant hormone auxin causes the seedling to bend towards the light. [2]
(c) If the pot is rotated 180° every day, how would the growth of the seedling be affected? [1]
END OF PAPER
Total Marks: 100
Answers
Tu
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TuitionGoWhere Practice Paper - Science Primary 6 PSLE (Answer Key)
TuitionGoWhere Practice Paper (AI) — Version 3
Subject: Science
Level: Primary 6 PSLE
Paper: Practice Paper (Full)
Duration: 1 h 45 min
Total Marks: 100
Section A: Multiple-Choice Questions (56 marks)
| Question | Answer | Explanation |
|---|---|---|
| 1 | (1) | The grasshopper eats grass (prey to grass) and is eaten by the frog (predator to frog). |
| 2 | (2) | Fungi (e.g., mould, yeast) do not make their own food, reproduce by spores, and lack chlorophyll. Organism Q matches these characteristics. |
| 3 | (3) | Mushroom is a fungus, not a plant. Fern, moss, and conifer are non-flowering plants. |
| 4 | (3) | The nucleus contains genetic material (DNA) and controls all cellular activities. |
| 5 | (2) | Bacteria are microscopic and can only be seen under a microscope. Ali is incorrect (some microorganisms are beneficial). Cindy is incorrect (yeast is a fungus). Devi is incorrect (mould reproduces by spores). |
| 6 | (1) | The egg stage does not feed. Larva, pupa, and adult stages feed (though pupa feeds minimally/does not feed in some species; at PSLE level, egg is the clear non-feeding stage). |
| 7 | (3) | Electrical wires need to conduct electricity (Yes) and be flexible (Yes) for installation. Material C fits. Material D conducts electricity but is not flexible. |
| 8 | (3) | Oxygen at room temperature has no definite volume or shape → Gas. |
| 9 | (1) | The steel paper clip becomes a temporary magnet by magnetic induction, with the near end developing opposite polarity to the magnet's pole, causing attraction. |
| 10 | (3) | Object Y rests on the bottom, meaning its density is greater than water (highest among the four). W floats (density < water), X is suspended (density ≈ water), Z is partially submerged (density < water but > W). |
| 11 | (1) | In a series circuit with identical bulbs, current is the same through both, so they light up with equal brightness. |
| 12 | (2) | The plateau at 100°C (10–15 min) represents boiling (change of state from liquid to gas). The first rise (0–10 min) is heating of solid/liquid; the plateau at 0°C would be melting, but the graph shows rising from 0°C, so 0–10 min is heating, not a change of state. |
| 13 | (2) | Condensation is the change of state from gas (water vapour) to liquid (water droplets). |
| 14 | (2) | Without light, photosynthesis cannot occur, so no starch is produced. Iodine solution remains yellow-brown (no blue-black colour). |
| 15 | (3) | Stomata (pores on the leaf surface) allow gaseous exchange (CO₂ in, O₂ out). |
| 16 | (3) | Gaseous exchange (oxygen and carbon dioxide) occurs in the alveoli (air sacs) where capillaries are in close contact. |
| 17 | (1) | Energy transfer between trophic levels is ~10%. Grass (10,000 J) → Grasshopper (1,000 J) → Frog (100 J) → Snake (10 J). |
| 18 | (3) | Structural adaptation: a physical feature of an organism's body (cactus thick stems for water storage). (1) and (4) are behavioural adaptations. (2) is a physiological/behavioural response. |
| 19 | (2) | A fixed pulley changes the direction of force only; it does not reduce the effort needed. Effort = Load = 50 N (ignoring friction). |
| 20 | (2) | Extension per 2 N = 4 cm (from 10→14, 14→18, 18→22). For 8 N (4 × 2 N), extension = 4 × 4 cm = 16 cm. Length = 10 cm + 16 cm = 26 cm. |
| 21 | (1) | Law of reflection: angle of incidence = angle of reflection = 30°. |
| 22 | (1) | Battery stores chemical energy → converted to electrical energy in circuit → bulb converts to light and heat energy. |
| 23 | (2) | Principle of moments: Load × Load arm = Effort × Effort arm. 40 N × 0.5 m = Effort × 1.0 m → Effort = 20 N. |
| 24 | (4) | Higher temperature increases the rate of dissolving (kinetic energy of water molecules increases). |
| 25 | (3) | Male gametes (pollen grains) are produced in the anther (part of the stamen). |
| 26 | (3) | Gravitational force acts on all objects with mass, regardless of contact. (1) False: non-living things exert forces. (2) False: friction opposes motion. (4) False: magnetic force acts through non-magnetic materials (e.g., glass, plastic). |
| 27 | (3) | [Assuming diagram shows two bulbs in parallel, then in series with third] Bulbs in parallel share current; the series bulb gets full current. The series bulb is brightest; parallel bulbs are dimmer but equal to each other. |
| 28 | (4) | [Assuming diagram shows electromagnet with more coils/voltage] Strength of electromagnet increases with number of coils, current (voltage), and using a soft iron core. |
Section B: Open-Ended Questions (44 marks)
29. Classification and Characteristics of Living Things [4 marks]
a) State two characteristics of living things shown by the mimosa plant when its leaves fold upon touching. [2]
Answer:
- Sensitivity / Response to stimuli – The plant detects the touch (stimulus) and responds by folding its leaves.
- Movement – The folding of leaves is a visible movement in response to the stimulus.
(Accept: "Respond to changes in the environment" and "Move")
b) The diagram below shows a young plant growing from a seed.
<image_placeholder> id: Q29b-fig1 type: diagram linked_question: Q29b description: Seedling emerging from seed, showing root growing downwards and shoot growing upwards. labels: Root, Shoot, Seed coat, Cotyledon values: None must_show: Germinating seed with root and shoot directions </image_placeholder>
Explain why the root grows downwards and the shoot grows upwards. [2]
Answer:
- The root grows downwards due to positive geotropism (gravitropism) — it grows in the direction of gravitational pull to anchor the plant and absorb water and minerals from the soil.
- The shoot grows upwards due to negative geotropism — it grows against gravity to reach sunlight for photosynthesis.
30. Cells and Microscopy [3 marks]
a) Complete the table below to show the function of each cell part. [2]
| Cell Part | Function |
|---|---|
| Cell membrane | Controls the movement of substances in and out of the cell. |
| Chloroplast | Contains chlorophyll to trap light energy for photosynthesis. |
| Cytoplasm | Jelly-like substance where most cellular activities / chemical reactions take place. |
| Nucleus | Controls all activities of the cell; contains genetic information (DNA). |
b) State one difference between a plant cell and an animal cell. [1]
Answer: Plant cells have a cell wall (and chloroplasts, large central vacuole), while animal cells do not.
(Any one correct difference: cell wall, chloroplasts, large vacuole, regular shape vs irregular shape)
31. Matter and Its Properties [4 marks]
a) The diagram below shows the arrangement of particles in three states of matter.
<image_placeholder> id: Q31a-fig1 type: diagram linked_question: Q31a description: Three boxes showing particle arrangement: Solid (tight, ordered), Liquid (close, random), Gas (far apart, random). labels: Solid, Liquid, Gas values: None must_show: Particle arrangements for three states </image_placeholder>
Complete the table below using the words: solid, liquid, gas. [2]
| Description | State of Matter |
|---|---|
| Particles are tightly packed in a fixed arrangement. | Solid |
| Particles are close together but can slide past one another. | Liquid |
| Particles are far apart and move freely in all directions. | Gas |
b) Substance X has a melting point of 50°C and a boiling point of 200°C. What is the state of substance X at 150°C? Explain your answer. [2]
Answer: Liquid.
At 150°C, the temperature is above the melting point (50°C) so it has melted, but below the boiling point (200°C) so it has not yet boiled. Hence, it exists as a liquid.
32. Heat and Temperature [4 marks]
a) The diagram below shows a metal spoon placed in a cup of hot tea.
<image_placeholder> id: Q32a-fig1 type: diagram linked_question: Q32a description: Cup of hot tea with metal spoon immersed. Heat arrows from tea to spoon handle. labels: Hot tea, Metal spoon, Handle values: None must_show: Spoon in hot liquid, heat conduction path </image_placeholder>
The handle of the metal spoon becomes hot after a while. Name the process of heat transfer and explain how it occurs in the metal spoon. [2]
Answer: Conduction.
Metal is a good conductor of heat. When the spoon is in hot tea, the particles at the immersed end gain kinetic energy and vibrate more vigorously. They collide with neighbouring particles, transferring kinetic energy along the spoon to the handle.
b) A beaker of water at 80°C is left in a room at 30°C. After 30 minutes, the water temperature drops to 50°C. Explain why the temperature of the water decreases. [2]
Answer: Heat is lost from the hotter water to the cooler surrounding air through the processes of conduction, convection, and radiation until thermal equilibrium is approached. The water loses thermal energy, so its temperature decreases.
33. Light and Shadows [4 marks]
a) The diagram below shows a torch shining on a wooden block. A screen is placed behind the block.
<image_placeholder> id: Q33a-fig1 type: diagram linked_question: Q33a description: Torch → Wooden block → Screen. Shadow formed on screen. Light rays shown as straight lines. labels: Torch, Wooden block, Screen, Shadow values: None must_show: Light source, opaque object, screen, shadow with umbra </image_placeholder>
A shadow is formed on the screen. State two properties of light shown by the formation of this shadow. [2]
Answer:
- Light travels in straight lines.
- Light is blocked by opaque objects (wooden block does not allow light to pass through).
b) The torch is moved closer to the wooden block. What happens to the size of the shadow on the screen? Explain your answer. [2]
Answer: The shadow becomes larger.
When the light source is closer to the object, the light rays diverge more, causing the opaque block to block a larger area on the screen, resulting in a bigger shadow.
34. Electrical Systems [5 marks]
a) The diagram below shows a circuit with two bulbs, B1 and B2, and two switches, S1 and S2.
<image_placeholder> id: Q34a-fig1 type: diagram linked_question: Q34a description: Battery with two parallel branches. Branch 1: S1 then B1. Branch 2: S2 then B2. Switches and bulbs in series within each branch. labels: Battery, S1, B1, S2, B2 values: None must_show: Parallel circuit with independent switches for each bulb </image_placeholder>
Complete the table below to show whether each bulb lights up (✓) or does not light up (✗). [2]
| Switch S1 | Switch S2 | Bulb B1 | Bulb B2 |
|---|---|---|---|
| Closed | Open | ✓ | ✗ |
| Open | Closed | ✗ | ✓ |
| Closed | Closed | ✓ | ✓ |
| Open | Open | ✗ | ✗ |
b) In the circuit above, the bulbs are connected in parallel. State one advantage of connecting bulbs in parallel compared to in series. [1]
Answer: If one bulb fuses (blows), the other bulb still lights up because the circuit for the other bulb remains complete.
(Accept: Each bulb gets the full voltage from the battery / bulbs are brighter than in series / each bulb can be controlled independently)
c) The diagram below shows a circuit with a battery, a switch, a bulb, and a conductor X.
<image_placeholder> id: Q34c-fig1 type: diagram linked_question: Q34c description: Series circuit: Battery → Switch → Bulb → Conductor X → back to Battery. Conductor X is a variable material. labels: Battery, Switch, Bulb, Conductor X values: None must_show: Series circuit with test conductor </image_placeholder>
The bulb lights up brightly when conductor X is a copper rod. When conductor X is replaced with a wooden rod, the bulb does not light up. Explain why. [2]
Answer: Copper is a good conductor of electricity — it allows electric current to flow through the closed circuit, lighting the bulb.
Wood is an insulator (poor conductor of electricity) — it does not allow electric current to flow, so the circuit is incomplete (open), and the bulb does not light up.
35. Forces and Energy [5 marks]
a) The diagram below shows a ball at position A on a frictionless track. It is released from rest and moves to position B, then up to position C.
<image_placeholder> id: Q35a-fig1 type: diagram linked_question: Q35a description: Roller coaster type track. A at highest point (start), B at lowest point, C at intermediate height (lower than A). Ball shown at A. labels: Position A, Position B, Position C, Height labels values: Height A > Height C > Height B must_show: Track with three labelled positions at different heights </image_placeholder>
i) At which position (A, B, or C) does the ball have the greatest kinetic energy? [1]
Answer: Position B (lowest point).
ii) Explain your answer in terms of energy conversion. [2]
Answer: At position A, the ball has maximum gravitational potential energy and zero kinetic energy (released from rest). As it rolls down to B, gravitational potential energy is converted to kinetic energy. At B (lowest height), potential energy is minimum, so kinetic energy is maximum. At C, some kinetic energy is converted back to potential energy as the ball rises.
b) A box of mass 5 kg is pushed across a horizontal floor with a constant force of 20 N. The frictional force between the box and the floor is 8 N. Calculate the acceleration of the box. [2]
Answer:
Net force = Applied force – Frictional force = 20 N – 8 N = 12 N
Using Newton’s Second Law: ( F = ma )
( a = \frac{F}{m} = \frac{12 \text{ N}}{5 \text{ kg}} = \mathbf{2.4 \text{ m/s}^2} )
36. Plant Transport System [4 marks]
a) The diagram below shows a cross-section of a stem.
<image_placeholder> id: Q36a-fig1 type: diagram linked_question: Q36a description: Stem cross-section showing vascular bundles arranged in a ring. Each bundle has xylem (inner) and phloem (outer). Labels for xylem, phloem, cambium. labels: Xylem, Phloem, Cambium, Epidermis, Cortex, Pith values: None must_show: Vascular bundle structure with xylem and phloem positions </image_placeholder>
Name the parts labelled X and Y and state one function of each. [2]
(Assuming X = Xylem, Y = Phloem based on standard diagram)
Answer:
- X: Xylem – Transports water and mineral salts from roots to other parts of the plant. Provides support to the plant.
- Y: Phloem – Transports food (sugar/sucrose) made in the leaves during photosynthesis to other parts of the plant (roots, stems, fruits, seeds).
b) A ring of bark (including phloem) is removed from a tree trunk as shown below.
<image_placeholder> id: Q36b-fig1 type: diagram linked_question: Q36b description: Tree trunk with a ring of bark removed (girdling). Swelling above the cut. labels: Removed bark ring, Swelling above cut, Normal bark below values: None must_show: Girdled tree trunk with swelling above cut </image_placeholder>
After a few weeks, a swelling appears above the cut. Explain why. [2]
Answer: The phloem (which transports food) is removed in the ring of bark. Food made in the leaves cannot be transported downwards past the cut, so it accumulates above the cut, causing the swelling. The xylem (water transport) remains intact, so the tree may survive for a while.
37. Human Circulatory System [4 marks]
a) The diagram below shows the human heart.
<image_placeholder> id: Q37a-fig1 type: diagram linked_question: Q37a description: Heart diagram showing four chambers: Right atrium, Right ventricle, Left atrium, Left ventricle. Major vessels: Vena cava, Pulmonary artery, Pulmonary vein, Aorta. Valves shown. labels: Right atrium, Right ventricle, Left atrium, Left ventricle, Vena cava, Pulmonary artery, Pulmonary vein, Aorta, Tricuspid valve, Bicuspid valve values: None must_show: Complete heart anatomy with chambers, vessels, valves </image_placeholder>
Name the chamber that pumps oxygen-rich blood to the rest of the body. [1]
Answer: Left ventricle
b) The table below shows the composition of blood in the pulmonary artery and pulmonary vein.
| Blood Vessel | Oxygen Content | Carbon Dioxide Content |
|---|---|---|
| Pulmonary artery | Low | High |
| Pulmonary vein | High | Low |
Explain why the blood in the pulmonary artery has low oxygen content. [2]
Answer: The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs to pick up oxygen. This blood has just returned from the body where oxygen was used up by cells for respiration, so it has low oxygen and high carbon dioxide.
c) State one function of the valves in the heart. [1]
Answer: Valves prevent the backflow of blood, ensuring it flows in one direction only (e.g., from atria to ventricles, from ventricles to arteries).
38. Reproduction in Plants [4 marks]
a) The diagram below shows the process of pollination and fertilisation in a flowering plant.
<image_placeholder> id: Q38a-fig1 type: diagram linked_question: Q38a description: Pollen grain on stigma → pollen tube grows down style → enters ovule through micropyle → male gamete fuses with female gamete (ovule). labels: Stigma, Style, Ovary, Ovule, Pollen grain, Pollen tube, Male gamete, Female gamete values: None must_show: Pollination to fertilisation sequence </image_placeholder>
i) Name the process where the pollen grain lands on the stigma. [1]
Answer: Pollination
ii) Describe what happens after pollination until a seed is formed. [3]
Answer:
- The pollen grain germinates and grows a pollen tube down the style into the ovary.
- The pollen tube enters the ovule through the micropyle.
- The male gamete (from the pollen tube) fuses with the female gamete (in the ovule) — this is fertilisation.
- The fertilised ovule develops into a seed, and the ovary develops into the fruit.
39. Adaptations and Environment [4 marks]
a) The diagram below shows a polar bear and a camel.
<image_placeholder> id: Q39a-fig1 type: diagram linked_question: Q39a description: Polar bear in Arctic (thick fur, blubber, white fur). Camel in desert (hump, thick eyelashes, wide feet). labels: Polar bear, Camel, Thick fur, Blubber, White fur, Hump, Thick eyelashes, Wide feet values: None must_show: Two animals with adaptation labels </image_placeholder>
State one structural adaptation of the polar bear for keeping warm and explain how it helps. [2]
Answer: Thick fur (or thick layer of fat/blubber).
The thick fur traps a layer of air close to the skin. Air is a poor conductor of heat, so this reduces heat loss from the bear’s body to the cold surroundings, keeping it warm.
b) The camel stores fat in its hump. State two ways this adaptation helps the camel survive in the desert. [2]
Answer:
- The fat can be broken down to release energy and water (metabolic water) when food and water are scarce.
- Concentrating fat in the hump reduces insulation over the rest of the body, allowing better heat loss during the hot day.
40. Environmental Interactions [4 marks]
a) The graph below shows the population of organism X and organism Y in a habitat over time.
<image_placeholder> id: Q40a-fig1 type: graph linked_question: Q40a description: Population vs Time graph. Two curves: Organism X (predator) peaks after Organism Y (prey). Classic predator-prey cycles. labels: Time, Population size, Organism X, Organism Y values: Cyclical peaks and troughs offset must_show: Predator-prey population cycles </image_placeholder>
Based on the graph, which organism is the predator and which is the prey? Explain your answer. [2]
Answer: Organism X is the predator; Organism Y is the prey.
The predator population peaks after the prey population peaks. When prey (Y) is abundant, predators (X) have more food, so their population increases. As predators increase, they eat more prey, causing the prey population to decrease. Then predator population decreases due to lack of food.
b) A new predator of organism Y is introduced into the habitat. Predict how the population of organism X will change in the short term. Explain your answer. [2]
Answer: The population of organism X will decrease.
The new predator competes with organism X for the same prey (organism Y). With more predators eating organism Y, the population of Y will decrease, leaving less food for organism X, so its population will drop.
End of Answer Key
Marking Notes:
- Section A: 2 marks per question (56 marks total).
- Section B: Marks as indicated (44 marks total).
- Accept scientifically accurate alternative phrasing.
- For calculation questions, award method marks if final answer is wrong but working is correct.
- Diagrams referenced are described in the question paper; students should refer to those.
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