▶️ Answer/Explanation
All living organisms share seven characteristics: movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition.
Photosynthesis is a specific form of nutrition carried out only by green plants, algae, and some bacteria — not by all living organisms (e.g. animals cannot photosynthesise).
✅ Answer: (C)
Photosynthesis is a specific form of nutrition carried out only by green plants, algae, and some bacteria — not by all living organisms (e.g. animals cannot photosynthesise).
✅ Answer: (C)
▶️ Answer/Explanation
Structures unique to plant cells (not in animal cells) include the cell wall, chloroplast, and permanent vacuole.
In this cell, the labelled structures Z and W correspond to plant-specific structures, while the nucleus (a structure common to both plant and animal cells) is missing from those labelled but present in other plant cells.
✅ Answer: (D)
In this cell, the labelled structures Z and W correspond to plant-specific structures, while the nucleus (a structure common to both plant and animal cells) is missing from those labelled but present in other plant cells.
✅ Answer: (D)
▶️ Answer/Explanation
Proteins are made from carbon, hydrogen, oxygen and nitrogen, built from small molecules called amino acids.
Fats are made only from carbon, hydrogen and oxygen, and are built from glucose-based small molecules — not amino acids.
✅ Answer: (D)
Fats are made only from carbon, hydrogen and oxygen, and are built from glucose-based small molecules — not amino acids.
✅ Answer: (D)
▶️ Answer/Explanation
Enzymes are biological catalysts that speed up the breakdown of large food molecules during chemical digestion.
Carbohydrates, hormones, and fatty acids do not catalyse digestive reactions.
✅ Answer: (B)
Carbohydrates, hormones, and fatty acids do not catalyse digestive reactions.
✅ Answer: (B)
▶️ Answer/Explanation
At point X, the rate of photosynthesis is still rising as light intensity increases, showing light is limiting.
Once the graph plateaus at higher light intensities, a different factor (e.g. \(CO_2\)) becomes limiting instead.
✅ Answer: (C)
Once the graph plateaus at higher light intensities, a different factor (e.g. \(CO_2\)) becomes limiting instead.
✅ Answer: (C)
▶️ Answer/Explanation
Bile emulsifies fats, breaking them into smaller droplets and increasing their surface area.
This makes it easier for lipase to digest the fats, though bile itself does not digest anything or contain enzymes.
✅ Answer: (C)
This makes it easier for lipase to digest the fats, though bile itself does not digest anything or contain enzymes.
✅ Answer: (C)
▶️ Answer/Explanation
Vessel X carries deoxygenated blood from the body into the heart, so it is the pulmonary artery leading to the lungs.
Vessel Y carries oxygenated blood back from the lungs, and chamber Z receiving this blood before pumping it to the body is the right ventricle.
✅ Answer: (D)
Vessel Y carries oxygenated blood back from the lungs, and chamber Z receiving this blood before pumping it to the body is the right ventricle.
✅ Answer: (D)
▶️ Answer/Explanation
In cold weather, more energy is needed to maintain a constant body temperature against heat loss.
This higher energy demand is met by a higher rate of respiration, releasing more energy from food.
✅ Answer: (A)
This higher energy demand is met by a higher rate of respiration, releasing more energy from food.
✅ Answer: (A)
▶️ Answer/Explanation
Normal phototropism relies on auxin accumulating unevenly, more on the shaded side, causing that side to elongate faster and bend towards light.
With a lightproof cover, all sides receive equal (no directional) light, so auxin stays evenly distributed and the shoot grows straight up.
✅ Answer: (B)
With a lightproof cover, all sides receive equal (no directional) light, so auxin stays evenly distributed and the shoot grows straight up.
✅ Answer: (B)
▶️ Answer/Explanation
The anther is the pollen-producing structure at the top of the stamen, labelled S in the diagram.
The ovary is the swollen base of the carpel containing ovules, labelled Q in the diagram.
✅ Answer: (D)
The ovary is the swollen base of the carpel containing ovules, labelled Q in the diagram.
✅ Answer: (D)
▶️ Answer/Explanation
Random mutations occasionally give some bacteria resistance to an antibiotic.
When the antibiotic is used, non-resistant bacteria die while resistant ones survive and reproduce — this is natural selection, not human-directed breeding.
✅ Answer: (C)
When the antibiotic is used, non-resistant bacteria die while resistant ones survive and reproduce — this is natural selection, not human-directed breeding.
✅ Answer: (C)
▶️ Answer/Explanation
An organism is a primary consumer when it feeds directly on phytoplankton, and a secondary consumer when it feeds on another consumer.
Fish feed on zooplankton (primary) and jellyfish feed on zooplankton too, but also fish feed on smaller consumers/jellyfish feed on other consumers — so both fish and jellyfish occupy both roles in this web.
✅ Answer: (A)
Fish feed on zooplankton (primary) and jellyfish feed on zooplankton too, but also fish feed on smaller consumers/jellyfish feed on other consumers — so both fish and jellyfish occupy both roles in this web.
✅ Answer: (A)
▶️ Answer/Explanation
This is eutrophication: dead algae provide extra organic matter for decomposers, which multiply rapidly.
These decomposers use up dissolved oxygen during respiration, causing fish to die from lack of oxygen.
✅ Answer: (A)
These decomposers use up dissolved oxygen during respiration, causing fish to die from lack of oxygen.
✅ Answer: (A)
▶️ Answer/Explanation
Hexane and octane are miscible liquids with different boiling points, so they must be separated by fractional distillation.
This requires a fractionating column fitted above the flask, allowing vapours to separate as they condense at different heights — shown in apparatus D.
✅ Answer: (D)
This requires a fractionating column fitted above the flask, allowing vapours to separate as they condense at different heights — shown in apparatus D.
✅ Answer: (D)
▶️ Answer/Explanation
Heating zinc carbonate produces zinc oxide (a new solid) and carbon dioxide gas: \(ZnCO_3 \rightarrow ZnO + CO_2\).
Since new substances with different properties are formed, this is thermal decomposition, a chemical change (and it absorbs energy, so it is not exothermic).
✅ Answer: (A)
Since new substances with different properties are formed, this is thermal decomposition, a chemical change (and it absorbs energy, so it is not exothermic).
✅ Answer: (A)
▶️ Answer/Explanation
The mass number (190) equals protons plus neutrons, and the proton number is 76.
So, \(\text{neutrons} = 190 – 76 = 114\).
✅ Answer: (B)
So, \(\text{neutrons} = 190 – 76 = 114\).
✅ Answer: (B)
▶️ Answer/Explanation
This question was officially discounted by Cambridge and no marks were awarded for any response.
Option A shows the chemically correct ionic equation (\(Ag^{+}_{(aq)} + Br^{-}_{(aq)} \rightarrow AgBr_{(s)}\)), but the question was removed from scoring due to an error in the original paper.
⚠️ Answer: Question discounted — no credit given to any option.
Option A shows the chemically correct ionic equation (\(Ag^{+}_{(aq)} + Br^{-}_{(aq)} \rightarrow AgBr_{(s)}\)), but the question was removed from scoring due to an error in the original paper.
⚠️ Answer: Question discounted — no credit given to any option.
▶️ Answer/Explanation
In this process, aluminium oxide (the ore, purified from bauxite) is dissolved in molten cryolite to lower its melting point, forming the electrolyte.
Aluminium ions gain electrons (are reduced) at the cathode, not oxidised, and cryolite is the solvent, not the ore itself.
✅ Answer: (D)
Aluminium ions gain electrons (are reduced) at the cathode, not oxidised, and cryolite is the solvent, not the ore itself.
✅ Answer: (D)
▶️ Answer/Explanation
Increasing concentration means more particles are packed into the same volume.
This makes collisions between reactant particles more frequent, increasing the reaction rate (unlike temperature, which raises particle energy).
✅ Answer: (B)
This makes collisions between reactant particles more frequent, increasing the reaction rate (unlike temperature, which raises particle energy).
✅ Answer: (B)
▶️ Answer/Explanation
The acid is heated first, then excess copper(II) oxide is added to ensure all acid reacts.
The mixture is then filtered to remove unreacted oxide, the filtrate is heated to concentrate it, left to crystallise, and finally the crystals are pressed dry.
✅ Answer: (C)
The mixture is then filtered to remove unreacted oxide, the filtrate is heated to concentrate it, left to crystallise, and finally the crystals are pressed dry.
✅ Answer: (C)
▶️ Answer/Explanation
Copper is a transition metal, and transition metals characteristically form coloured compounds (e.g. blue copper(II) sulfate) and basic metal oxides.
Bromine and CO are non-metal/covalent substances, and sodium is a reactive metal forming a simple white basic oxide, not coloured compounds.
✅ Answer: (C)
Bromine and CO are non-metal/covalent substances, and sodium is a reactive metal forming a simple white basic oxide, not coloured compounds.
✅ Answer: (C)
▶️ Answer/Explanation
Catalytic converters convert carbon monoxide and nitrogen monoxide into less harmful gases (carbon dioxide and nitrogen) using a catalyst.
Sulfur dioxide is not produced from fuel combustion in significant amounts affected by catalytic converters, so it is not one of the target gases.
✅ Answer: (B)
Sulfur dioxide is not produced from fuel combustion in significant amounts affected by catalytic converters, so it is not one of the target gases.
✅ Answer: (B)
▶️ Answer/Explanation
Calcium carbonate (limestone) is added to the blast furnace and decomposes to form calcium oxide.
This calcium oxide reacts with silica impurities in the ore to form molten slag (calcium silicate), which is removed separately from the iron.
✅ Answer: (A)
This calcium oxide reacts with silica impurities in the ore to form molten slag (calcium silicate), which is removed separately from the iron.
✅ Answer: (A)
▶️ Answer/Explanation
The Contact process, used to manufacture sulfuric acid, converts sulfur dioxide into sulfur trioxide.
This step uses vanadium(V) oxide (\(V_2O_5\)) as the catalyst — iron and nickel are used in other industrial processes (Haber process, hydrogenation) instead.
✅ Answer: (D)
This step uses vanadium(V) oxide (\(V_2O_5\)) as the catalyst — iron and nickel are used in other industrial processes (Haber process, hydrogenation) instead.
✅ Answer: (D)
▶️ Answer/Explanation
Limestone is calcium carbonate, not calcium oxide, but it is heated to manufacture lime (calcium oxide), so statement 2 is correct.
Limestone (or lime made from it) is basic and neutralises acidic industrial waste, so statement 3 is correct; statement 4 is wrong since it is used to neutralise acidic (not alkaline) soil.
✅ Answer: (C)
Limestone (or lime made from it) is basic and neutralises acidic industrial waste, so statement 3 is correct; statement 4 is wrong since it is used to neutralise acidic (not alkaline) soil.
✅ Answer: (C)
▶️ Answer/Explanation
Naphtha is a hydrocarbon fraction, and like all hydrocarbons it burns completely to form carbon dioxide and water.
It is a mixture of hydrocarbons (not a single compound like methane), and it is not the fraction present in bottled gas (that is the more volatile refinery gas fraction).
✅ Answer: (A)
It is a mixture of hydrocarbons (not a single compound like methane), and it is not the fraction present in bottled gas (that is the more volatile refinery gas fraction).
✅ Answer: (A)
▶️ Answer/Explanation
In addition polymerisation, the monomer must have a carbon-to-carbon double bond that opens up to form single bonds in the polymer chain.
The repeat unit shows two methyl (\(CH_3\)) side groups on adjacent carbons, so the monomer must have a \(C=C\) double bond with two methyl groups attached, matching option B.
✅ Answer: (B)
The repeat unit shows two methyl (\(CH_3\)) side groups on adjacent carbons, so the monomer must have a \(C=C\) double bond with two methyl groups attached, matching option B.
✅ Answer: (B)
▶️ Answer/Explanation
The graph shows a straight sloped line for the first 10 s, meaning acceleration (the gradient) is constant, not increasing.
After 10 s the line becomes horizontal, showing constant speed — so acceleration does not “steadily increase and then become constant” as stated in option B.
✅ Answer: (B)
After 10 s the line becomes horizontal, showing constant speed — so acceleration does not “steadily increase and then become constant” as stated in option B.
✅ Answer: (B)
▶️ Answer/Explanation
The beam’s weight, \(W = mg = 12 \times 10 = 120\text{ N}\), acts at its centre, 2.0 m from the pivot.
Taking moments about the pivot: \(F \times 4.0 = 120 \times 2.0\), so \(F = \frac{240}{4.0} = 60\text{ N}\).
✅ Answer: (C)
Taking moments about the pivot: \(F \times 4.0 = 120 \times 2.0\), so \(F = \frac{240}{4.0} = 60\text{ N}\).
✅ Answer: (C)
▶️ Answer/Explanation
Pressure is given by \(P = \frac{F}{A}\), so rearranging gives \(A = \frac{F}{P}\).
Substituting values: \(A = \frac{14}{70} = 0.20\text{ m}^2\).
✅ Answer: (A)
Substituting values: \(A = \frac{14}{70} = 0.20\text{ m}^2\).
✅ Answer: (A)
▶️ Answer/Explanation
Tides are caused mainly by the gravitational pull of the Moon on the Earth’s oceans, since it is much closer than the Sun despite being far less massive.
The Sun has a smaller secondary effect on tides, while Mars and the Earth itself are not the driving cause.
✅ Answer: (C)
The Sun has a smaller secondary effect on tides, while Mars and the Earth itself are not the driving cause.
✅ Answer: (C)
▶️ Answer/Explanation
Increasing the temperature of a gas increases the kinetic energy of its particles, making them move faster, not more slowly.
The other statements correctly describe random particle motion and how gas pressure arises from particle collisions with the container walls.
✅ Answer: (A)
The other statements correctly describe random particle motion and how gas pressure arises from particle collisions with the container walls.
✅ Answer: (A)
▶️ Answer/Explanation
In grilling, thermal energy travels through the air from the red-hot heater to the food by infrared radiation, since air is a poor conductor.
In frying, thermal energy passes through the solid metal pan by conduction, as vibrating particles pass energy to neighbouring particles.
✅ Answer: (C)
In frying, thermal energy passes through the solid metal pan by conduction, as vibrating particles pass energy to neighbouring particles.
✅ Answer: (C)
▶️ Answer/Explanation
A plane mirror always produces a virtual image that is the same size as the object, at the same distance behind the mirror as the object is in front.
The image is laterally inverted (left and right are swapped), not inverted top to bottom.
✅ Answer: (B)
The image is laterally inverted (left and right are swapped), not inverted top to bottom.
✅ Answer: (B)
▶️ Answer/Explanation
Using \(n = \frac{\sin i}{\sin r}\), rearranged to \(\sin r = \frac{\sin i}{n} = \frac{\sin 34°}{1.5} = \frac{0.559}{1.5} \approx 0.373\).
Taking the inverse sine gives \(r \approx 22°\).
✅ Answer: (A)
Taking the inverse sine gives \(r \approx 22°\).
✅ Answer: (A)
▶️ Answer/Explanation
Iron is used because it is easily magnetised when current flows and easily demagnetised when current stops, making it ideal for a temporary electromagnet.
Steel retains magnetism (used for permanent magnets), while aluminium and copper are not magnetic materials at all.
✅ Answer: (C)
Steel retains magnetism (used for permanent magnets), while aluminium and copper are not magnetic materials at all.
✅ Answer: (C)
▶️ Answer/Explanation
The magnetic field around a straight current-carrying wire forms concentric circles centred on the wire.
Using the right-hand grip rule with the current going into the page, the field circles clockwise (as seen from the reader’s viewpoint), matching diagram A.
✅ Answer: (A)
Using the right-hand grip rule with the current going into the page, the field circles clockwise (as seen from the reader’s viewpoint), matching diagram A.
✅ Answer: (A)
▶️ Answer/Explanation
Induced e.m.f. depends on how quickly magnetic field lines are cut, which is affected by conductor length, field strength, and speed of motion.
The resistance of the conductor affects current flow once the circuit is complete, but it does not determine the size of the e.m.f. generated.
✅ Answer: (B)
The resistance of the conductor affects current flow once the circuit is complete, but it does not determine the size of the e.m.f. generated.
✅ Answer: (B)
▶️ Answer/Explanation
Since \(P = VI\) and power is constant, increasing voltage means the current must decrease.
Power loss in the cables is \(I^2R\), so a lower current results in less power loss.
✅ Answer: (A)
Power loss in the cables is \(I^2R\), so a lower current results in less power loss.
✅ Answer: (A)
▶️ Answer/Explanation
Using Fleming’s left-hand rule, with the field running from the North to the South pole and the current direction as shown, the thumb (force direction) points downwards.
This is the motor effect: the wire experiences a mechanical force perpendicular to both the current and the magnetic field.
✅ Answer: (A)
This is the motor effect: the wire experiences a mechanical force perpendicular to both the current and the magnetic field.
✅ Answer: (A)