Question 1 (Sub-topic – B1.1)
All living organisms can break down nutrient molecules to release energy. What is this process?
A. excretion
B. growth
C. nutrition
D. respiration
▶️Answer/Explanation
Answer: D. respiration
Explanation: Respiration is the process by which living organisms break down nutrient molecules to release energy. This energy is used for various cellular activities. Excretion, growth, and nutrition are other life processes but do not directly involve the breakdown of nutrient molecules to release energy.
Question 2 (Sub-topic – B3.2)
The diagram shows the stages of an experiment.
A piece of potato with a mass of 10.0 g is placed in a beaker with a dilute sugar solution. After 30 minutes, the potato is carefully dried and its mass is now 10.4 g. Which statement is a correct explanation for the increase in mass?
A. Sugar has moved into the cells of the potato by osmosis.
B. Sugar has moved out of the cells of the potato by osmosis.
C. Water has moved into the cells of the potato by osmosis.
D. Water has moved out of the cells of the potato by osmosis.
▶️Answer/Explanation
Answer: C. Water has moved into the cells of the potato by osmosis.
Explanation: Osmosis is the movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane. In this case, the dilute sugar solution has a higher water potential than the potato cells, so water moves into the potato cells, causing the mass to increase.
Question 3 (Sub-topic – C2.1)
Which molecule contains carbon?
A. ammonia
B. fat
C. sulfuric acid
D. water
▶️Answer/Explanation
Answer: B. fat
Explanation: Fat is an organic molecule that contains carbon atoms. Ammonia (NH₃), sulfuric acid (H₂SO₄), and water (H₂O) are inorganic molecules and do not contain carbon.
Question 4 (Sub-topic – B5.1)
Which graph shows the effect of pH on the rate of activity of an enzyme?
A. rate of enzyme activity increases linearly with pH
B. rate of enzyme activity decreases linearly with pH
C. rate of enzyme activity increases to a maximum and then decreases
D. rate of enzyme activity remains constant with pH
▶️Answer/Explanation
Answer: C. rate of enzyme activity increases to a maximum and then decreases
Explanation: Enzymes have an optimal pH at which they function most efficiently. As pH deviates from this optimal value, the enzyme’s activity decreases. Therefore, the graph showing the rate of enzyme activity increasing to a maximum and then decreasing with pH is correct.
Question 5 (Sub-topic – B6.1)
The diagram shows an experiment to investigate photosynthesis. When leaves photosynthesise, they store some carbohydrates as starch. Potassium hydroxide absorbs carbon dioxide.
After standing in sunlight for 10 hours, leaf L contained no starch but leaf M contained a lot of starch. What does this show?
A. A leaf cannot make starch in a sealed flask.
B. A leaf cannot make starch without carbon dioxide.
C. A leaf cannot make starch without light.
D. A leaf cannot make starch without oxygen.
▶️Answer/Explanation
Answer: B. A leaf cannot make starch without carbon dioxide.
Explanation: Potassium hydroxide absorbs carbon dioxide, so leaf L was deprived of CO₂ and could not photosynthesize to produce starch. Leaf M, which had access to CO₂, was able to photosynthesize and produce starch. This shows that carbon dioxide is necessary for photosynthesis and starch production.
Question 6 (Sub-topic – B7.1)
Which component of a balanced diet is a source of energy?
A. carbohydrates
B. minerals
C. vitamins
D. water
▶️Answer/Explanation
Answer: A. carbohydrates
Explanation: Carbohydrates are the primary source of energy in a balanced diet. They are broken down into glucose, which is used by the body for energy. Minerals, vitamins, and water are essential for various bodily functions but do not provide energy.
Question 7 (Sub-topic – B8.1)
The diagram shows a transverse section through a plant stem.
Which tissue is X?
A. mesophyll
B. phloem
C. epidermis
D. xylem
▶️Answer/Explanation
Answer: B. phloem
Explanation: The phloem is responsible for transporting sucrose and amino acids in plants. In a transverse section of a plant stem, the phloem is typically located near the outer part of the vascular bundle, which matches the description of tissue X in the diagram.
Question 8 (Sub-topic – B12.1)
A person ran up as many stairs as they could in one minute.
What would be the effect on their breathing?
A. depth of breathing decreased, rate of breathing decreased
B. depth of breathing decreased, rate of breathing increased
C. depth of breathing increased, rate of breathing decreased
D. depth of breathing increased, rate of breathing increased
▶️Answer/Explanation
Answer: D. depth of breathing increased, rate of breathing increased
Explanation: During vigorous exercise, such as running up stairs, the body requires more oxygen to meet the increased energy demand. This leads to an increase in both the depth (volume) and rate (frequency) of breathing to supply more oxygen to the muscles and remove carbon dioxide.
Question 9 (Sub-topic – B13.2)
A student wrote some notes about hormones. She wrote: ‘A hormone is produced by a ……1…… . It is transported in the blood ……2…… . It alters the activity of one or more ……3…… organs.’
Which row correctly completes gaps 1, 2 and 3?
A. 1: gland, 2: cells, 3: specific
B. 1: gland, 2: plasma, 3: target
C. 1: tissue, 2: cells, 3: specific
D. 1: tissue, 2: plasma, 3: target
▶️Answer/Explanation
Answer: B. 1: gland, 2: plasma, 3: target
Explanation: Hormones are chemical messengers produced by glands and transported in the blood plasma. They act on specific target organs to regulate various physiological processes.
Question 10 (Sub-topic – B15.3)
In which structure is pollen made?
A. anther
B. ovary
C. sepal
D. stigma
▶️Answer/Explanation
Answer: A. anther
Explanation: Pollen is produced in the anther, which is part of the stamen in a flower. The ovary, sepal, and stigma are other parts of the flower but are not involved in pollen production.
Question 11 (Sub-topic – B16.3)
Two parents with genotypes of BB and Bb were crossed. Which genotypes and ratios would be expected in the offspring?
A. 1 BB: 1 Bb
B. 1 Bb: 1 bb
C. 3 BB: 1 Bb
D. 3 Bb: 1 BB
▶️Answer/Explanation
Answer: A. 1 BB: 1 Bb
Explanation: When crossing BB (homozygous dominant) with Bb (heterozygous), the possible genotypes of the offspring are BB and Bb. The Punnett square shows a 1:1 ratio of BB to Bb offspring.
Question 12 (Sub-topic – B18.2)
A producer is an organism which makes its own organic nutrients.
Which process does a producer use and what is the source of energy?
A. photosynthesis, dead organic matter
B. respiration, sunlight
C. photosynthesis, sunlight
D. respiration, dead organic matter
▶️Answer/Explanation
Answer: C. photosynthesis, sunlight
Explanation: Producers, such as plants, use photosynthesis to convert sunlight into chemical energy stored in organic nutrients like glucose. Respiration is a process used by all organisms to release energy from organic nutrients, but it is not the process by which producers make their own nutrients.
Question 13 (Sub-topic – B18.3)
The diagram shows a simplified carbon cycle.
Which labelled arrow represents respiration?
A. CO₂ → green plants
B. green plants → animals
C. animals → CO₂
D. fossil fuels → CO₂
▶️Answer/Explanation
Answer: C. animals → CO₂
Explanation: Respiration in animals releases carbon dioxide (CO₂) as a byproduct. Therefore, the arrow from animals to CO₂ represents respiration in the carbon cycle.
Question 14 (Sub-topic – C2.2)
The protons, neutrons, and electrons in a particle are shown.
Which symbol represents this particle?
A. F
B. F⁻
C. Ne
D. Ne⁺
▶️Answer/Explanation
Answer: B. F⁻
Explanation: The particle has 9 protons (fluorine), 10 neutrons, and 10 electrons. Since it has one more electron than protons, it is a fluoride ion (F⁻).
Question 15 (Sub-topic – C2.5)
Which row describes the properties of a covalent compound?
| Melting Point (°C) | Solubility in Water | Undergoes Electrolysis When Molten |
|---|---|---|
| A. 100 | Insoluble | No |
| B. 110 | Soluble | Yes |
| C. 950 | Insoluble | No |
| D. 2200 | Soluble | Yes |
▶️Answer/Explanation
Answer: A. 100, Insoluble, No
Explanation: Covalent compounds generally have low melting points (e.g., 100°C), are often insoluble in water, and do not conduct electricity or undergo electrolysis when molten.
Question 16 (Sub-topic – C2.5)
A model of a molecule is shown.
Which row shows the formula of this molecule and describes the type of bonding between the atoms?
| Formula | Bonding |
|---|---|
| A. 2BH₃ | Covalent |
| B. 2BH₃ | Ionic |
| C. B₂H₆ | Covalent |
| D. B₂H₆ | Ionic |
▶️Answer/Explanation
Answer: C. B₂H₆, Covalent
Explanation: The molecule shown is diborane (B₂H₆), which consists of boron and hydrogen atoms bonded together by covalent bonds.
Question 17 (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?
| 1 | 2 |
|---|---|
| A. anode | bromine |
| B. anode | chlorine |
| C. cathode | bromine |
| D. cathode | chlorine |
▶️Answer/Explanation
Answer: A. anode, bromine
Explanation: The positive electrode is the anode, and the orange color indicates the formation of bromine (Br₂), which is a halogen.
Question 18 (Sub-topic – C5.1)
The same masses of four substances are added separately to four samples of 10 cm³ of dilute hydrochloric acid at 22 °C. The final temperature of each reaction mixture is measured. Which reaction is most endothermic?
| Substance | Final Temperature (°C) |
|---|---|
| A | 29 |
| B | 27 |
| C | 20 |
| D | 17 |
▶️Answer/Explanation
Answer: D. 17
Explanation: An endothermic reaction absorbs heat from the surroundings, causing the temperature to decrease. The reaction with the lowest final temperature (17°C) is the most endothermic.
Question 19 (Sub-topic – C6.2)
Dilute hydrochloric acid is added to excess solid calcium carbonate. Which change increases the rate of this reaction?
A. decrease the concentration of the acid
B. decrease the volume of the acid
C. reduce the size of the solid particles
D. reduce the temperature
▶️Answer/Explanation
Answer: C. reduce the size of the solid particles
Explanation: Reducing the size of solid particles increases the surface area available for the reaction, which increases the rate of reaction. Decreasing the concentration, volume, or temperature would slow down the reaction.
Question 20 (Sub-topic – C7.1)
A gas turns damp litmus paper white. What is the gas?
A. carbon dioxide
B. chlorine
C. hydrogen chloride
D. sulfur dioxide
▶️Answer/Explanation
Answer: B. chlorine
Explanation: Chlorine gas (Cl₂) bleaches damp litmus paper, turning it white. Carbon dioxide, hydrogen chloride, and sulfur dioxide do not have this effect.
Question 21 (Sub-topic – C8.3)
Which statement about the elements in Group I and in Group VII of the Periodic Table is correct?
A. Chlorine has a darker colour than iodine.
B. Each molecule of a halogen contains one atom.
C. Potassium reacts with cold water more vigorously than lithium.
D. The melting point of lithium is lower than the melting point of sodium.
▶️Answer/Explanation
Answer: C. Potassium reacts with cold water more vigorously than lithium.
Explanation: In Group I (alkali metals), reactivity increases down the group. Potassium (K) is below lithium (Li) in the group, so it reacts more vigorously with cold water. Chlorine is lighter in color than iodine, halogens are diatomic (e.g., Cl₂), and lithium has a lower melting point than sodium.
Question 22 (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. to increase the hardness of the steel
Explanation: Manganese is added to steel to increase its hardness and strength, making it suitable for tools like drills that need to withstand high stress and wear.
Question 23 (Sub-topic – C10.1)
What is a chemical test for water?
A. It turns anhydrous cobalt(II) chloride white.
B. It turns anhydrous copper(II) sulfate blue.
C. It turns blue copper(II) sulfate white.
D. It turns pink cobalt(II) chloride blue.
▶️Answer/Explanation
Answer: B. It turns anhydrous copper(II) sulfate blue.
Explanation: Anhydrous copper(II) sulfate (white) turns blue in the presence of water, making it a reliable chemical test for water.
Question 24 (Sub-topic – C10.2)
Which process does not produce carbon dioxide?
A. complete combustion of fossil fuels
B. reaction of an acid with a carbonate
C. respiration in plants
D. rusting iron
▶️Answer/Explanation
Answer: D. rusting iron
Explanation: Rusting of iron is an oxidation process that forms iron(III) oxide (Fe₂O₃) and does not produce carbon dioxide. Combustion, acid-carbonate reactions, and respiration all produce CO₂.
Question 25 (Sub-topic – C10.2)
Which statements about limestone are correct?
1. Limestone is used to neutralise industrial waste products.
2. Limestone is used to treat acidic soil.
3. Thermal decomposition of limestone produces calcium oxide.
A. 1 and 2 only
B. 1 and 3 only
C. 2 and 3 only
D. 1, 2 and 3
▶️Answer/Explanation
Answer: D. 1, 2 and 3
Explanation: Limestone (calcium carbonate) is used to neutralize acidic waste and soil. When heated, it undergoes thermal decomposition to produce calcium oxide (quicklime) and carbon dioxide.
Question 26 (Sub-topic – C11.6)
Four molecules are shown.
Which structure represents ethanol?
A. H–C–C–OH
B. H–C–O–C–H
C. H–C–C–H
D. H–C–O–H
▶️Answer/Explanation
Answer: A. H–C–C–OH
Explanation: Ethanol has the molecular formula C₂H₅OH, which corresponds to the structure H–C–C–OH.
Question 27 (Sub-topic – C11.5)
Which statement about ethene, C₂H₄, is not correct?
A. It is an unsaturated hydrocarbon.
B. It is produced by cracking.
C. It is used to make a polymer.
D. It turns aqueous bromine brown.
▶️Answer/Explanation
Answer: D. It turns aqueous bromine brown.
Explanation: Ethene is an unsaturated hydrocarbon (A), produced by cracking (B), and used to make polymers like polyethylene (C). However, it decolorizes aqueous bromine (turns it from brown to colorless), so statement D is incorrect.
Question 28 (Sub-topic – P1.2)
A student uses a stopwatch to measure the time taken for a ball to drop 2.0 m to the ground. The measurement is taken five times. These are the results: 20.16 s, 20.22 s, 20.14 s, 20.22 s, 20.26 s. Which value for the time taken should be used?
A. 20.16 s
B. 20.20 s
C. 20.22 s
D. 20.26 s
▶️Answer/Explanation
Answer: B. 20.20 s
Explanation: The average of the five measurements should be used to minimize errors. The average of 20.16, 20.22, 20.14, 20.22, and 20.26 is 20.20 s.
Question 29 (Sub-topic – P1.5.3)
A student wishes to determine the centre of mass of a piece of card.
She makes five holes in the card.
She suspends the card from a pin, as shown.
She hangs a load from a thread attached to the pin and marks the line of the thread on the card.
The student repeats the procedure using a different hole. What is the smallest number of lines that she needs to draw to determine the position of the centre of mass of the card?
A. 1
B. 2
C. 3
D. 4
▶️Answer/Explanation
Answer: B. 2
Explanation: The centre of mass is the point where the lines intersect. Drawing two lines from different suspension points is sufficient to determine the intersection point.
Question 30 (Sub-topic – P1.7)
When driving cars on soft sand, drivers are advised to reduce the pressure of the air in the tyres. Why does this cause the cars to sink less into the sand?
A. The area of the tyres in contact with the sand is decreased.
B. The area of the tyres in contact with the sand is increased.
C. The downward force on the sand is decreased.
D. The downward force on the sand is increased.
▶️Answer/Explanation
Answer: B. The area of the tyres in contact with the sand is increased.
Explanation: Reducing tyre pressure increases the contact area between the tyres and the sand, distributing the car’s weight over a larger area and reducing the pressure on the sand, which prevents sinking.
Question 31 (Sub-topic – P1.6.1)
Which type of energy does an object have due to its motion?
A. elastic potential
B. gravitational potential
C. kinetic
D. nuclear
▶️Answer/Explanation
Answer: C. kinetic
Explanation: Kinetic energy is the energy an object possesses due to its motion. Elastic potential, gravitational potential, and nuclear energy are forms of stored energy, not energy due to motion.
Question 32 (Sub-topic Code: P2.1.2)
Which labelled arrow on the diagram represents condensation?
A. liquid → gas
B. gas → liquid
C. solid → liquid
D. liquid → solid
▶️Answer/Explanation
Answer: B. gas → liquid
Explanation: Condensation is the process by which a gas changes into a liquid, so the arrow from gas to liquid represents condensation.
Question 33 (Sub-topic – P2.3.1)
Four rods have the same dimensions. They are made of four different metals and are all at room temperature. All the rods are heated equally at one end for the same length of time. The final temperature of the other end of each rod is shown in the table. Which rod is the worst conductor of heat?
| Rod | Final Temperature (°C) |
|---|---|
| A | 50 |
| B | 62 |
| C | 70 |
| D | 82 |
▶️Answer/Explanation
Answer: A. 50
Explanation: The rod with the lowest final temperature (50°C) is the worst conductor of heat because less heat has been transferred to the other end.
Question 34 (Sub-topic – P3.2.1)
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. 70°
Explanation: The angle of reflection is equal to the angle of incidence. If the angle of incidence is 70°, the angle of reflection is also 70°.
Question 35 (Sub-topic – P4.2.1)
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. The rod is a positively charged electrical insulator.
Explanation: The negatively charged strip is attracted to the rod, indicating that the rod is positively charged. Since the rod is held in the hand and does not discharge, it is likely an insulator.
Question 36 (Sub-topic – P4.2.2)
An ammeter is used to measure the current in a metal wire. Which row describes the current and how the ammeter is connected to the wire?
| Description of Current | How Ammeter is Connected |
|---|---|
| A. flow of electrons | in parallel with the wire |
| B. flow of electrons | in series with the wire |
| C. flow of protons | in parallel with the wire |
| D. flow of protons | in series with the wire |
▶️Answer/Explanation
Answer: B. flow of electrons, in series with the wire
Explanation: Current in a metal wire is the flow of electrons, and an ammeter must be connected in series to measure the current.
Question 37 (Sub-topic – P4.3.2)
Three resistors are connected in series with a battery, as shown.
The current at point P is 6.0 A.
What is the current at point Q?
A. 0 A
B. 2.0 A
C. 3.0 A
D. 6.0 A
▶️Answer/Explanation
Answer: D. 6.0 A
Explanation: In a series circuit, the current is the same at all points. Therefore, the current at point Q is also 6.0 A.
Question 38 (Sub-topic – P4.4)
A hairdryer is protected by a 10 A fuse. What is the purpose of the fuse?
A. It decreases the current in the hairdryer to 10 A when the current is more than 10 A.
B. It increases the current in the hairdryer to 10 A when the current is less than 10 A.
C. It maintains a constant temperature in the hairdryer.
D. It melts when the current in the hairdryer is greater than 10 A.
▶️Answer/Explanation
Answer: D. It melts when the current in the hairdryer is greater than 10 A.
Explanation: A fuse is a safety device that melts and breaks the circuit if the current exceeds a certain value (in this case, 10 A), preventing damage to the appliance or wiring.
Question 39 (Sub-topic – P4.5.3)
The diagrams show the cross-section of a straight wire carrying a current into the page.
Which diagram shows the pattern and direction of the magnetic field around the wire?
A. concentric circles clockwise
B. concentric circles anticlockwise
C. straight lines parallel to the wire
D. straight lines perpendicular to the wire
▶️Answer/Explanation
Answer: B. concentric circles anticlockwise
Explanation: The magnetic field around a current-carrying wire forms concentric circles. Using the right-hand grip rule, if the current is into the page, the magnetic field direction is anticlockwise.
Question 40 (Sub-topic – P5.2.2)
Which description of an α-particle is correct?
A. It contains 2 protons and 2 neutrons.
B. It contains 2 protons and 4 neutrons.
C. It contains 4 protons and 2 neutrons.
D. It contains 4 protons and 4 neutrons.
▶️Answer/Explanation
Answer: A. It contains 2 protons and 2 neutrons.
Explanation: An α-particle is a helium nucleus, which consists of 2 protons and 2 neutrons.