Question 1 (Sub-topic – B6.1)
The list shows some requirements of living things.
- light
- carbon dioxide
- water
- mineral ions
What do plants need to make glucose?
A) 1 and 2 only
B) 2 and 3 only
C) 3 and 4
D) 1, 2 and 3
▶️Answer/Explanation
Answer: D) 1, 2 and 3
Explanation: Plants require light, carbon dioxide, and water to carry out photosynthesis, which is the process by which they produce glucose. Mineral ions are important for plant growth but are not directly involved in the photosynthesis process.
Question 2 (Sub-topic – B2.1)
Which structure is only found in plant cells?
A) cell membrane
B) cytoplasm
C) nucleus
D) vacuole
▶️Answer/Explanation
Answer: D) vacuole
Explanation: While both plant and animal cells have a cell membrane, cytoplasm, and nucleus, plant cells typically have a large central vacuole that is not found in animal cells. This vacuole helps maintain cell turgor and stores nutrients and waste products.
Question 3 (Sub-topic – C2.2)
Which molecule contains carbon?
A) ammonia
B) fat
C) sulfuric acid
D) water
▶️Answer/Explanation
Answer: B) fat
Explanation: Fats are organic molecules that contain carbon atoms. Ammonia (NH₃), sulfuric acid (H₂SO₄), and water (H₂O) are inorganic molecules and do not contain carbon.
Question 4 (Sub-topic – B5.1)
An investigation was carried out to see the effect of pH on the activity of an enzyme found in the human alimentary canal. The graph shows the results obtained.
What is the enzyme?
A) a protease found in the mouth
B) a protease found in the stomach
C) an amylase found in the mouth
D) an amylase found in the stomach
▶️Answer/Explanation
Answer: B) a protease found in the stomach
Explanation: The stomach has a highly acidic environment (pH around 2), which is optimal for the activity of proteases like pepsin. The graph likely shows high enzyme activity at low pH, indicating that the enzyme is a protease found in the stomach.
Question 5 (Sub-topic – B6.1)
What will cause plant leaves to turn yellow?
A) a lack of magnesium in the soil
B) a lack of starch in the leaves
C) a reduction in the rate of photosynthesis
D) a reduction in the rate of respiration
▶️Answer/Explanation
Answer: A) a lack of magnesium in the soil
Explanation: Magnesium is a key component of chlorophyll, the pigment responsible for the green color in leaves. A deficiency in magnesium leads to chlorosis, where leaves turn yellow due to a lack of chlorophyll.
Question 6 (Sub-topic – B7.1)
Which nutrient is well provided by citrus fruits such as oranges and lemons?
A) carbohydrate
B) protein
C) vitamin C
D) vitamin D
▶️Answer/Explanation
Answer: C) vitamin C
Explanation: Citrus fruits like oranges and lemons are rich in vitamin C, which is essential for the immune system, skin health, and the absorption of iron.
Question 7 (Sub-topic – B9.2)
Which row shows the state of the heart valves whilst the atria are contracting and the ventricles are relaxing?
▶️Answer/Explanation
Answer: A) open, closed
Explanation: When the atria contract, blood flows into the ventricles, so the atrioventricular valves (between the atria and ventricles) are open. The semilunar valves (between the ventricles and arteries) are closed to prevent backflow of blood into the ventricles.
Question 8 (Sub-topic – B11.1)
Which diagram shows the rate and depth of breathing of a person before and during exercise?
A) before: shallow and slow; during: deep and fast
B) before: deep and slow; during: shallow and fast
C) before: shallow and fast; during: deep and slow
D) before: deep and fast; during: shallow and slow
▶️Answer/Explanation
Answer: A) before: shallow and slow; during: deep and fast
Explanation: During exercise, the body requires more oxygen and produces more carbon dioxide, leading to an increase in both the rate and depth of breathing. Before exercise, breathing is typically slower and shallower.
Question 9 (Sub-topic – B13.1)
A person touches a hot object with their hand. They quickly pull their hand away. Which statement is correct?
A) The effector is their hand.
B) The effector is the hot object.
C) The receptor is in the muscles of their arm.
D) The receptor is in the skin of their hand.
▶️Answer/Explanation
Answer: D) The receptor is in the skin of their hand.
Explanation: The receptor that detects the heat is located in the skin. When the receptor detects the heat, it sends a signal to the nervous system, which then triggers the effector (muscles in the arm) to pull the hand away.
Question 10 (Sub-topic – B15.3)
What is a characteristic of an insect-pollinated flower compared with a wind-pollinated flower?
▶️Answer/Explanation
Answer: A) anthers inside flower, anthers outside flower
Explanation: Insect-pollinated flowers typically have their anthers inside the flower to ensure that pollen is transferred to visiting insects. Wind-pollinated flowers often have their anthers exposed outside the flower to allow pollen to be easily carried by the wind.
Question 11 (Sub-topic – B16.1)
Wing length in fruit flies is controlled by a single pair of alleles. The diagram shows the results of crosses between fruit flies.
What is the probability of individuals 6 and 7 producing another offspring with long wings?
- A: 12.5%
- B: 25%
- C: 50%
- D: 75%
▶️Answer/Explanation
Answer: C
Explanation: The probability of individuals 6 and 7 producing another offspring with long wings is 50%. This is because the cross between individuals 6 and 7 is a monohybrid cross, and the offspring have a 50% chance of inheriting the long wing allele.
Question 12 (Sub-topic – B18.1)
What is an ecosystem?
- A: a chart showing the flow of energy from one organism to another
- B: a diagram giving the energy level of an organism in its environment
- C: a network of interconnected organisms
- D: a unit containing all of the organisms and their environment
▶️Answer/Explanation
Answer: D
Explanation: An ecosystem is a unit that contains all the organisms and their environment, including the interactions between them. It is not just a chart or diagram but a functional unit where energy and nutrients are cycled.
Question 13 (Sub-topic – B18.3)
The diagram shows a simplified carbon cycle. Which labelled arrow represents respiration?
- A: CO₂
- B: green plants
- C: animals
- D: fossil fuels
▶️Answer/Explanation
Answer: C
Explanation: Respiration is the process by which animals release carbon dioxide (CO₂) into the atmosphere. Therefore, the arrow labelled “animals” represents respiration in the carbon cycle.
Question 14 (Sub-topic – C6.1)
Which row identifies physical changes and chemical changes?
- A: cooking an egg and ice melting | rusting of iron
- B: ice melting and water boiling | burning wood
- C: mixing sand and water | baking a cake and water boiling
- D: rusting of iron and baking a cake | solid dissolving and ethanol evaporating
▶️Answer/Explanation
Answer: B
Explanation: Physical changes involve changes in the state or appearance of a substance without altering its chemical composition (e.g., ice melting and water boiling). Chemical changes involve the formation of new substances (e.g., burning wood).
Question 15 (Sub-topic – C3.2)
Carbon dioxide is produced in a reaction. It is collected in a gas syringe. The readings on the gas syringe are shown:
Initial reading: 7 cm³
Final reading: 43 cm³
What is the mass of carbon dioxide gas produced?
- A: 0.0015 g
- B: 0.0018 g
- C: 0.0660 g
- D: 0.0788 g
▶️Answer/Explanation
Answer: C
Explanation: The volume of CO₂ produced is 43 cm³ – 7 cm³ = 36 cm³. Using the molar volume of a gas at room temperature (24 dm³/mol), the number of moles of CO₂ is 36 cm³ / 24000 cm³/mol = 0.0015 mol. The molar mass of CO₂ is 44 g/mol, so the mass of CO₂ produced is 0.0015 mol × 44 g/mol = 0.0660 g.
Question 16 (Sub-topic – C4.1)
The diagram shows the electrolysis of a compound.
When the switch is closed, the solution around electrode P turns orange because a halogen is formed. The positive electrode P is called the ……1……, and the halogen is ……2…… .
Which words complete gaps 1 and 2?
- A: anode | bromine
- B: anode | chlorine
- C: cathode | bromine
- D: cathode | chlorine
▶️Answer/Explanation
Answer: A
Explanation: The positive electrode is the anode, where oxidation occurs. The orange color indicates the formation of bromine gas (Br₂), which is a halogen.
Question 17 (Sub-topic – C6.2)
Excess magnesium reacts with 25 cm³ of 0.1 mol/dm³ hydrochloric acid. The dashed line shows the volume of gas made over time. The experiment is repeated using excess magnesium and 25 cm³ of 0.05 mol/dm³ hydrochloric acid. Which line shows the results for this experiment?
- A: Line A
- B: Line B
- C: Line C
- D: Line D
▶️Answer/Explanation
Answer: D
Explanation: The reaction rate is slower with a lower concentration of hydrochloric acid (0.05 mol/dm³), so the volume of gas produced over time will increase more slowly compared to the original experiment with 0.1 mol/dm³ acid. Line D represents this slower reaction rate.
Question 18 (Sub-topic – C6.3)
Which equation represents a redox reaction?
- A: CaCO₃ → CaO + CO₂
- B: Cu(OH)₂ → CuO + H₂O
- C: LiOH + HCl → LiCl + H₂O
- D: 2Na + 2H₂O → 2NaOH + H₂
▶️Answer/Explanation
Answer: D
Explanation: A redox reaction involves both oxidation and reduction. In option D, sodium (Na) is oxidized to Na⁺, and hydrogen in water (H₂O) is reduced to H₂ gas. This is a redox reaction.
Question 19 (Sub-topic – C7.1)
Nitrous oxide, N₂O, is a neutral oxide. Which statement about nitrous oxide is correct?
- A: It does not react with acids or with alkalis.
- B: It reacts only with acids.
- C: It reacts only with alkalis.
- D: It reacts with both acids and alkalis.
▶️Answer/Explanation
Answer: A
Explanation: Nitrous oxide (N₂O) is a neutral oxide, meaning it does not react with acids or alkalis. It is chemically inert under normal conditions.
Question 20 (Sub-topic – C9.4)
When a small piece of potassium is placed in water, hydrogen gas is given off very quickly. Which element reacts in a similar way?
- A: copper
- B: iron
- C: magnesium
- D: sodium
▶️Answer/Explanation
Answer: D
Explanation: Sodium (Na) is in the same group as potassium (K) in the periodic table and reacts similarly with water, producing hydrogen gas and forming an alkaline solution.
Question 21 (Sub-topic – C9.3)
Why does the steel used to make a drill contain manganese?
- A: to increase the density of the steel
- B: to increase the hardness of the steel
- C: to increase the malleability of the steel
- D: to increase the melting point of the steel
▶️Answer/Explanation
Answer: B
Explanation: Manganese is added to steel to increase its hardness and strength, making it suitable for use in tools like drills.
Question 22 (Sub-topic – C9.5)
A block of zinc is attached to an underground steel pipe as shown.
The zinc stops the steel rusting by sacrificial protection. Which statement is not correct?
- A: Zinc is more reactive than the iron in steel.
- B: Zinc is oxidised in preference to the iron in steel.
- C: Zinc prevents oxygen from reaching the steel.
- D: Zinc transfers electrons to the iron in the steel.
▶️Answer/Explanation
Answer: C
Explanation: Zinc does not prevent oxygen from reaching the steel. Instead, it acts as a sacrificial anode, being oxidized in preference to the iron, thus protecting the steel from rusting.
Question 23 (Sub-topic – C10.2)
Which row identifies a gas removed from exhaust emissions and a gas produced by a catalytic converter?
- A: carbon dioxide | carbon monoxide
- B: carbon dioxide | oxygen
- C: nitrogen monoxide | carbon monoxide
- D: nitrogen monoxide | oxygen
▶️Answer/Explanation
Answer: D
Explanation: A catalytic converter removes nitrogen monoxide (NO) from exhaust emissions and produces oxygen (O₂) as one of the products of the reaction.
Question 24 (Sub-topic – C8.2)
The Contact process is used to manufacture sulfuric acid. Which step in the Contact process is reversible?
- A: sulfur reacting with oxygen
- B: sulfur dioxide reacting with oxygen
- C: sulfuric acid reacting with sulfur trioxide
- D: oleum, H₂S₂O₇, reacting with water
▶️Answer/Explanation
Answer: B
Explanation: The reaction between sulfur dioxide (SO₂) and oxygen (O₂) to form sulfur trioxide (SO₃) is reversible in the Contact process.
Question 25 (Sub-topic –C7.3)
Calcium carbonate (limestone) is a base. Which uses of limestone depend on it acting as a base?
- A: 1 and 2
- B: 2 and 3
- C: 2 and 4
- D: 3 and 4
▶️Answer/Explanation
Answer: C
Explanation: Limestone acts as a base in neutralizing acid waste (2) and in the treatment of soil (4). It does not act as a base in making lime (1) or in stone buildings (3).
Question 26 (Sub-topic – C11.6)
Four molecules are shown. Which structure represents ethanol?
- A: Structure A
- B: Structure B
- C: Structure C
- D: Structure D
▶️Answer/Explanation
Answer: A
Explanation: Ethanol has the chemical formula C₂H₅OH, and Structure A correctly represents this molecule.
Question 27 (Sub-topic – C11.4)
The cracking of decane molecules is represented by the equation shown.
What is Y?
- A: C₄H₈
- B: C₄H₁₀
- C: C₇H₁₄
- D: C₇H₁₆
▶️Answer/Explanation
Answer: B
Explanation: The cracking of decane (C₁₀H₂₂) produces smaller alkanes and alkenes. In this case, Y is C₄H₁₀, which is butane.
Question 28 (Sub-topic – P1.5)
A student is investigating the extension of a spring. The diagrams show the spring before and after a 0.20 N load is added.
What is the spring constant of the spring?
- A: 0.070 N/cm
- B: 0.16 N/cm
- C: 0.25 N/cm
- D: 4.0 N/cm
▶️Answer/Explanation
Answer: C
Explanation: The spring constant (k) is calculated using Hooke’s Law: F = kx, where F is the force and x is the extension. Here, k = F/x = 0.20 N / 0.8 cm = 0.25 N/cm.
Question 29 (Sub-topic – P1.7)
The table gives the weight and total area of contact with the ground of four animals. Which animal exerts the least pressure on the ground?
- A: beaver
- B: cat
- C: duck
- D: mouse
▶️Answer/Explanation
Answer: C
Explanation: Pressure is calculated as force divided by area. The duck has the largest area of contact with the ground relative to its weight, so it exerts the least pressure.
Question 30 (Sub-topic – P1.6)
A ball falls vertically downwards. Which energy transfer takes place as the ball accelerates downwards?
- A: gravitational potential to elastic potential (strain)
- B: gravitational potential to kinetic
- C: elastic potential (strain) to kinetic
- D: kinetic to gravitational potential
▶️Answer/Explanation
Answer: B
Explanation: As the ball falls, its gravitational potential energy is converted into kinetic energy as it accelerates downwards.
Question 31 (Sub-topic – P1.6)
A 250 W electric motor lifts a 50 N load through a height of 4.0 m in 3.0 s. What is the efficiency of this system of lifting the load?
- A: 15%
- B: 27%
- C: 38%
- D: 67%
▶️Answer/Explanation
Answer: B
Explanation: The work done in lifting the load is W = F × d = 50 N × 4.0 m = 200 J. The power input is 250 W, so the energy input in 3.0 s is E = P × t = 250 W × 3.0 s = 750 J. The efficiency is (200 J / 750 J) × 100% = 26.7%, which is approximately 27%.
Question 32 (Sub-topic – P2.2)
Which labelled arrow on the diagram represents condensation?
- A: A
- B: B
- C: C
- D: D
▶️Answer/Explanation
Answer: A
Explanation: Condensation is the process by which a gas turns into a liquid. Arrow A represents this phase change.
Question 33 (Sub-topic – P2.1)
A sealed cylinder contains gas. The average speed of the molecules of the gas increases but the average distance between them remains the same.
How does this affect the pressure of the gas and its volume?
- A: decreases | increases
- B: decreases | no change
- C: increases | increases
- D: increases | no change
▶️Answer/Explanation
Answer: D
Explanation: If the average speed of the gas molecules increases, the pressure of the gas increases because the molecules collide with the walls of the container more frequently and with greater force. The volume remains the same because the cylinder is sealed.
Question 34 (Sub-topic – P3.4)
Four loudspeakers vibrate at different frequencies. Which frequency produces a sound with the largest wavelength and can be heard by a human?
- A: 15 Hz
- B: 150 Hz
- C: 2.5 kHz
- D: 25 kHz
▶️Answer/Explanation
Answer: B
Explanation: The wavelength of sound is inversely proportional to its frequency. A lower frequency (150 Hz) produces a longer wavelength, and it is within the audible range for humans (20 Hz to 20 kHz).
Question 35 (Sub-topic – P3.2)
The diagram shows a ray of light striking a plane mirror.
What is the angle of reflection?
- A: 20°
- B: 40°
- C: 70°
- D: 90°
▶️Answer/Explanation
Answer: C
Explanation: The angle of reflection is equal to the angle of incidence. In this case, the angle of incidence is 70°, so the angle of reflection is also 70°.
Question 36 (Sub-topic – P3.2)
Which diagram shows a converging lens forming a real image of an object O?
- A: Diagram A
- B: Diagram B
- C: Diagram C
- D: Diagram D
▶️Answer/Explanation
Answer: C
Explanation: A converging lens forms a real image when the object is placed beyond the focal point. Diagram C correctly shows this scenario.
Question 37 (Sub-topic – P3.1)
The diagram represents a wave in air. Molecules are closer together in region P than they are in region Q.
Which type of wave is represented, and in which direction do the molecules vibrate?
- A: longitudinal | parallel to the wave direction
- B: longitudinal | perpendicular to the wave direction
- C: transverse | parallel to the wave direction
- D: transverse | perpendicular to the wave direction
▶️Answer/Explanation
Answer: A
Explanation: The wave is longitudinal because the molecules vibrate parallel to the direction of wave propagation. Region P represents compression, where molecules are closer together.
Question 38 (Sub-topic – P4.2)
A rod is rubbed with a dry piece of cloth. A scientist holds the rod in her hand and brings it close to a negatively charged plastic strip. The strip is suspended by an insulating thread. As the rod approaches the plastic strip, the strip moves towards the rod.
Which statement is correct?
- A: The rod is a negatively charged electrical conductor.
- B: The rod is a negatively charged electrical insulator.
- C: The rod is a positively charged electrical conductor.
- D: The rod is a positively charged electrical insulator.
▶️Answer/Explanation
Answer: D
Explanation: The rod is positively charged because it attracts the negatively charged plastic strip. It is an insulator because it does not allow the charge to flow through it.
Question 39 (Sub-topic – P4.5)
The diagram shows a wire carrying an electric current in the direction shown. The wire is at right angles to a magnetic field that is directed into the page.
A force acts on the wire because of the current and the magnetic field.
In which labelled direction does this force act?
- A: A
- B: B
- C: C
- D: D
▶️Answer/Explanation
Answer: B
Explanation: According to Fleming’s Left-Hand Rule, the force on a current-carrying wire in a magnetic field is perpendicular to both the current and the magnetic field. In this case, the force acts in direction B.
Question 40 (Sub-topic – P5.2)
The table gives information about the deflection of radiation in an electric field and in a magnetic field.
Which row is correct?
- A: alpha | yes | yes
- B: alpha | no | yes
- C: gamma | yes | yes
- D: gamma | no | yes
▶️Answer/Explanation
Answer: A
Explanation: Alpha particles are positively charged and are deflected by both electric and magnetic fields. Gamma radiation is not deflected by either field.