▶️ Answer/Explanation
The bladderwort detects a nearby swimming animal and traps it, showing sensitivity — the ability to detect and respond to a stimulus.
It then digests the trapped animal, absorbing nutrients from it, which shows nutrition — taking in materials for energy and growth.
No excretion or growth process is described in the diagram.
✅ Answer: (D)
It then digests the trapped animal, absorbing nutrients from it, which shows nutrition — taking in materials for energy and growth.
No excretion or growth process is described in the diagram.
✅ Answer: (D)
▶️ Answer/Explanation
Osmosis is defined as the net movement of water molecules from a region of higher water potential to a region of lower water potential.
This movement must occur through a partially permeable membrane, which allows water molecules through but restricts larger solute molecules.
Options with “fully permeable” or reversed water-potential direction are incorrect definitions.
✅ Answer: (C)
This movement must occur through a partially permeable membrane, which allows water molecules through but restricts larger solute molecules.
Options with “fully permeable” or reversed water-potential direction are incorrect definitions.
✅ Answer: (C)
▶️ Answer/Explanation
A purple colour with the biuret test confirms the presence of protein.
A white emulsion with the ethanol test confirms the presence of fat.
Iodine staying brown (not blue-black) shows starch is absent.
✅ Answer: (A)
A white emulsion with the ethanol test confirms the presence of fat.
Iodine staying brown (not blue-black) shows starch is absent.
✅ Answer: (A)
▶️ Answer/Explanation
The graph shows starch mass falling fastest (steepest decline) at \( 40\,^\circ\text{C} \), meaning amylase is breaking it down quickest at that temperature.
At \( 10\,^\circ\text{C} \) and \( 25\,^\circ\text{C} \) the enzyme has low kinetic energy so the reaction is slow.
At \( 70\,^\circ\text{C} \) the enzyme is denatured, so little or no starch is broken down.
✅ Answer: (C)
At \( 10\,^\circ\text{C} \) and \( 25\,^\circ\text{C} \) the enzyme has low kinetic energy so the reaction is slow.
At \( 70\,^\circ\text{C} \) the enzyme is denatured, so little or no starch is broken down.
✅ Answer: (C)
▶️ Answer/Explanation
Nitrate ions are absorbed from the soil by plant roots.
They are combined with sugars produced in photosynthesis to make amino acids, which are then built into proteins.
Nitrate ions are not needed to make starch, are not found in chloroplasts, and are not part of the cell sap.
✅ Answer: (D)
They are combined with sugars produced in photosynthesis to make amino acids, which are then built into proteins.
Nitrate ions are not needed to make starch, are not found in chloroplasts, and are not part of the cell sap.
✅ Answer: (D)
▶️ Answer/Explanation
Chemical digestion breaks down large insoluble molecules (starch, protein, fat) into small soluble molecules using enzymes.
This happens mainly in the organs where digestive juices act on food, which in this diagram are labelled P and R.
Q and S represent regions such as the mouth/oesophagus or large intestine, where little or no chemical breakdown of this kind occurs.
✅ Answer: (A)
This happens mainly in the organs where digestive juices act on food, which in this diagram are labelled P and R.
Q and S represent regions such as the mouth/oesophagus or large intestine, where little or no chemical breakdown of this kind occurs.
✅ Answer: (A)
▶️ Answer/Explanation
The pulmonary vein carries oxygenated blood from the lungs back to the heart.
Veins carry blood towards the heart, so the correct vessel is the one with its arrow pointing from the lungs into the heart.
This corresponds to vessel B in the diagram.
✅ Answer: (B)
Veins carry blood towards the heart, so the correct vessel is the one with its arrow pointing from the lungs into the heart.
This corresponds to vessel B in the diagram.
✅ Answer: (B)
▶️ Answer/Explanation
Yeast respires anaerobically in the absence of oxygen, a process also called alcoholic fermentation.
The glucose is broken down to produce ethanol (alcohol) and carbon dioxide, releasing a small amount of energy.
This differs from anaerobic respiration in muscles, where glucose → lactic acid instead.
✅ Answer: (A)
The glucose is broken down to produce ethanol (alcohol) and carbon dioxide, releasing a small amount of energy.
This differs from anaerobic respiration in muscles, where glucose → lactic acid instead.
✅ Answer: (A)
▶️ Answer/Explanation
In bright light, the pupil must become smaller to reduce the amount of light entering the eye and protect the retina.
This happens when the circular muscles of the iris contract while the radial muscles relax.
The combined effect narrows the central opening (pupil), reducing light entry.
✅ Answer: (A)
This happens when the circular muscles of the iris contract while the radial muscles relax.
The combined effect narrows the central opening (pupil), reducing light entry.
✅ Answer: (A)
▶️ Answer/Explanation
Sexual reproduction involves the fusion of the nuclei of two gametes, each of which is haploid (one set of chromosomes).
This fusion restores the full chromosome number, producing a diploid zygote and offspring.
Asexual reproduction, by contrast, involves no gamete fusion at all, so options A and B are incorrect.
✅ Answer: (C)
This fusion restores the full chromosome number, producing a diploid zygote and offspring.
Asexual reproduction, by contrast, involves no gamete fusion at all, so options A and B are incorrect.
✅ Answer: (C)
▶️ Answer/Explanation
The black form of the moth first appeared as the result of a mutation, a random genetic change producing a new allele.
No human breeding programme selected the moths, so the shift in proportions is due to natural selection, not artificial selection.
Black moths were better camouflaged and survived better on polluted, darker tree bark, and pale moths survived better once pollution decreased.
✅ Answer: (D)
No human breeding programme selected the moths, so the shift in proportions is due to natural selection, not artificial selection.
Black moths were better camouflaged and survived better on polluted, darker tree bark, and pale moths survived better once pollution decreased.
✅ Answer: (D)
▶️ Answer/Explanation
Energy flows from the Sun to green plants (producers), which make their own food by photosynthesis.
X sits between the producers and the carnivores (animals), meaning it must eat the plants directly.
An organism that eats plants directly is a herbivore, making it the primary consumer in the chain.
✅ Answer: (C)
X sits between the producers and the carnivores (animals), meaning it must eat the plants directly.
An organism that eats plants directly is a herbivore, making it the primary consumer in the chain.
✅ Answer: (C)
▶️ Answer/Explanation
Excess nitrate ions first cause rapid growth of producers such as algae, blocking light to deeper plants.
Without light, deeper producers die, providing large amounts of organic matter for decomposers to break down.
Decomposers respire aerobically at a higher rate, using up dissolved oxygen, which then causes animals to die from lack of oxygen.
✅ Answer: (B)
Without light, deeper producers die, providing large amounts of organic matter for decomposers to break down.
Decomposers respire aerobically at a higher rate, using up dissolved oxygen, which then causes animals to die from lack of oxygen.
✅ Answer: (B)
▶️ Answer/Explanation
Excess copper oxide is added so that all the sulfuric acid reacts, leaving unreacted solid copper oxide in the mixture.
Since copper oxide is insoluble, it can be separated from the aqueous copper sulfate solution by filtration, leaving the copper oxide as the residue.
Crystallisation would instead be used afterwards to obtain solid copper sulfate crystals from the filtrate.
✅ Answer: (D)
Since copper oxide is insoluble, it can be separated from the aqueous copper sulfate solution by filtration, leaving the copper oxide as the residue.
Crystallisation would instead be used afterwards to obtain solid copper sulfate crystals from the filtrate.
✅ Answer: (D)
▶️ Answer/Explanation
A molecule of a compound must contain two or more different types of atom joined together in fixed proportions.
Diagrams showing only one type of atom (whether single or joined) represent an element, not a compound.
Diagram B shows molecules made of two different atom types bonded together, representing a compound.
✅ Answer: (B)
Diagrams showing only one type of atom (whether single or joined) represent an element, not a compound.
Diagram B shows molecules made of two different atom types bonded together, representing a compound.
✅ Answer: (B)
▶️ Answer/Explanation
Statement 2 is correct: one mole of any element has a mass in grams equal to its relative atomic mass, so one mole of \(^{12}\text{C}\) has a mass of 12 g.
Statement 3 is correct: one mole of any substance, including carbon, contains the Avogadro constant, \(6.02 \times 10^{23}\) particles.
Statement 1 is wrong (equal moles of any element contain the same number of atoms) and statement 4 is wrong (one mole of any gas at r.t.p. occupies 24 dm3, not 32 dm3).
✅ Answer: (C)
Statement 3 is correct: one mole of any substance, including carbon, contains the Avogadro constant, \(6.02 \times 10^{23}\) particles.
Statement 1 is wrong (equal moles of any element contain the same number of atoms) and statement 4 is wrong (one mole of any gas at r.t.p. occupies 24 dm3, not 32 dm3).
✅ Answer: (C)
▶️ Answer/Explanation
In dilute aqueous potassium chloride, the ions present are K⁺, Cl⁻, H⁺ and OH⁻ (from water).
At the cathode, the least reactive positive ion is discharged; since potassium is more reactive than hydrogen, H⁺ ions are discharged instead of K⁺.
This means hydrogen gas is produced at the cathode, while potassium remains in solution.
✅ Answer: (B)
At the cathode, the least reactive positive ion is discharged; since potassium is more reactive than hydrogen, H⁺ ions are discharged instead of K⁺.
This means hydrogen gas is produced at the cathode, while potassium remains in solution.
✅ Answer: (B)
▶️ Answer/Explanation
Testing for hydrogen gas with a lighted splint produces a “pop” sound, caused by the rapid combustion of hydrogen with oxygen.
Combustion reactions release thermal energy to the surroundings, so this is an exothermic process.
Boiling water and thermal decomposition of limestone or cracking of alkanes all require a continuous input of heat, making them endothermic instead.
✅ Answer: (D)
Combustion reactions release thermal energy to the surroundings, so this is an exothermic process.
Boiling water and thermal decomposition of limestone or cracking of alkanes all require a continuous input of heat, making them endothermic instead.
✅ Answer: (D)
▶️ Answer/Explanation
The steeper graph reaches its final gas volume more quickly, showing experiment 1 has the higher rate of reaction.
Increasing acid concentration means more acid particles in the same volume, so collisions between reacting particles happen more frequently.
Activation energy is a property of the reaction itself and does not change between the two experiments, so it cannot be the reason.
✅ Answer: (B)
Increasing acid concentration means more acid particles in the same volume, so collisions between reacting particles happen more frequently.
Activation energy is a property of the reaction itself and does not change between the two experiments, so it cannot be the reason.
✅ Answer: (B)
▶️ Answer/Explanation
An oxidising agent is a species that is itself reduced while causing another species to be oxidised.
In \(Zn^{2+} + Mg \rightarrow Zn + Mg^{2+}\), the zinc ion gains electrons to become zinc metal — it is reduced — while magnesium is oxidised.
In all the other equations, zinc itself loses electrons (is oxidised), meaning it acts as the reducing agent, not the oxidising agent.
✅ Answer: (C)
In \(Zn^{2+} + Mg \rightarrow Zn + Mg^{2+}\), the zinc ion gains electrons to become zinc metal — it is reduced — while magnesium is oxidised.
In all the other equations, zinc itself loses electrons (is oxidised), meaning it acts as the reducing agent, not the oxidising agent.
✅ Answer: (C)
▶️ Answer/Explanation
Potassium is a metal, so potassium oxide is a basic oxide, not an acidic oxide as listed.
Sulfur dioxide is a non-metal oxide, so it is an acidic oxide, not a basic oxide as listed.
Carbon dioxide is correctly acidic and sodium oxide is correctly basic, so only potassium oxide and sulfur dioxide are misplaced.
✅ Answer: (B)
Sulfur dioxide is a non-metal oxide, so it is an acidic oxide, not a basic oxide as listed.
Carbon dioxide is correctly acidic and sodium oxide is correctly basic, so only potassium oxide and sulfur dioxide are misplaced.
✅ Answer: (B)
▶️ Answer/Explanation
Copper is an element, it forms coloured ions (blue \( \text{Cu}^{2+} \) solutions), and its oxide, CuO, is a basic oxide.
Br2 and Na do not form coloured ions or basic oxides, and CO is a compound rather than an element.
Only copper satisfies all three overlapping properties.
✅ Answer: (C)
Br2 and Na do not form coloured ions or basic oxides, and CO is a compound rather than an element.
Only copper satisfies all three overlapping properties.
✅ Answer: (C)
▶️ Answer/Explanation
Group VIII noble gases have a full outer shell of electrons.
This stable electron arrangement means they have no tendency to gain, lose or share electrons, so they do not readily react.
Being gaseous or monatomic is a physical description, not the reason for their unreactivity.
✅ Answer: (D)
This stable electron arrangement means they have no tendency to gain, lose or share electrons, so they do not readily react.
Being gaseous or monatomic is a physical description, not the reason for their unreactivity.
✅ Answer: (D)
▶️ Answer/Explanation
A metal can be extracted by heating with carbon only if it is less reactive than carbon, allowing carbon to displace it from its oxide.
Aluminium is more reactive than carbon, so carbon cannot reduce aluminium oxide — aluminium must instead be extracted by electrolysis.
Copper, iron and zinc are all less reactive than carbon and can be extracted by carbon reduction.
✅ Answer: (A)
Aluminium is more reactive than carbon, so carbon cannot reduce aluminium oxide — aluminium must instead be extracted by electrolysis.
Copper, iron and zinc are all less reactive than carbon and can be extracted by carbon reduction.
✅ Answer: (A)
▶️ Answer/Explanation
Adding water to anhydrous (white) copper(II) sulfate turns it blue, and hydrated (blue) copper(II) sulfate simply dissolves to give a blue solution.
Adding water to anhydrous (blue) cobalt(II) chloride turns it pink, and hydrated (pink) cobalt(II) chloride dissolves to give a pink solution.
So every watch-glass, once water is added, ends up as either a blue or a pink solution.
✅ Answer: (A)
Adding water to anhydrous (blue) cobalt(II) chloride turns it pink, and hydrated (pink) cobalt(II) chloride dissolves to give a pink solution.
So every watch-glass, once water is added, ends up as either a blue or a pink solution.
✅ Answer: (A)
▶️ Answer/Explanation
X does not decolourise bromine water, so it is a saturated alkane; with 2 carbons this is ethane, \(C_2H_6\).
Y decolourises bromine water, so it is an unsaturated alkene; with 3 carbons this is propene, \(C_3H_6\).
Comparing hydrogen atoms: X has 6 and Y has 6, so the difference is \(6 – 6 = 0\).
✅ Answer: (A)
Y decolourises bromine water, so it is an unsaturated alkene; with 3 carbons this is propene, \(C_3H_6\).
Comparing hydrogen atoms: X has 6 and Y has 6, so the difference is \(6 – 6 = 0\).
✅ Answer: (A)
▶️ Answer/Explanation
Fermentation of glucose produces ethanol (the organic liquid) and carbon dioxide gas.
Ethanol is widely used as a solvent, not as a monomer for addition polymerisation.
Carbon dioxide gas turns limewater milky, which is the standard test for this gas.
✅ Answer: (C)
Ethanol is widely used as a solvent, not as a monomer for addition polymerisation.
Carbon dioxide gas turns limewater milky, which is the standard test for this gas.
✅ Answer: (C)
▶️ Answer/Explanation
An object moving with constant speed covers equal distances in equal time intervals.
This is represented by a distance–time graph that is a straight line with a constant, non-zero gradient.
Graph A shows this straight-line pattern, matching constant speed motion.
✅ Answer: (A)
This is represented by a distance–time graph that is a straight line with a constant, non-zero gradient.
Graph A shows this straight-line pattern, matching constant speed motion.
✅ Answer: (A)
▶️ Answer/Explanation
For each object, the resultant force is the difference between the two opposing forces, and acceleration is found using \(a = \frac{F}{m}\).
For A: \(\frac{80-10}{10} = 7\ \text{m/s}^2\).
For B: \(\frac{240-90}{15} = 10\ \text{m/s}^2\).
For C: \(\frac{160-100}{12} = 5\ \text{m/s}^2\).
For D: \(\frac{150-60}{20} = 4.5\ \text{m/s}^2\).
Comparing all four values, object B has the largest resultant acceleration.
✅ Answer: (B)
For A: \(\frac{80-10}{10} = 7\ \text{m/s}^2\).
For B: \(\frac{240-90}{15} = 10\ \text{m/s}^2\).
For C: \(\frac{160-100}{12} = 5\ \text{m/s}^2\).
For D: \(\frac{150-60}{20} = 4.5\ \text{m/s}^2\).
Comparing all four values, object B has the largest resultant acceleration.
✅ Answer: (B)
▶️ Answer/Explanation
Fossil fuels such as coal, oil and natural gas formed over millions of years and are being used up far faster than they can form.
Because they cannot be replenished within a human timescale, they are classed as non-renewable.
Tides, geothermal heat and wind are naturally replenished and are therefore renewable energy resources.
✅ Answer: (A)
Because they cannot be replenished within a human timescale, they are classed as non-renewable.
Tides, geothermal heat and wind are naturally replenished and are therefore renewable energy resources.
✅ Answer: (A)
▶️ Answer/Explanation
Cooling a gas reduces the kinetic energy of its molecules, so the average speed of the molecules decreases.
Slower-moving molecules collide with the container walls less often and with less force per collision.
Fewer, gentler collisions per unit area mean the pressure of the gas decreases.
✅ Answer: (A)
Slower-moving molecules collide with the container walls less often and with less force per collision.
Fewer, gentler collisions per unit area mean the pressure of the gas decreases.
✅ Answer: (A)
▶️ Answer/Explanation
A large bulb holds more liquid, so a given temperature rise causes a bigger volume expansion, giving a larger response.
A narrow tube means that same volume of expanded liquid has to travel further up the tube, producing a longer, more visible column movement.
Combining a large bulb with a narrow tube therefore gives the greatest, most easily read change for a small temperature change — the most sensitive thermometer.
✅ Answer: (B)
A narrow tube means that same volume of expanded liquid has to travel further up the tube, producing a longer, more visible column movement.
Combining a large bulb with a narrow tube therefore gives the greatest, most easily read change for a small temperature change — the most sensitive thermometer.
✅ Answer: (B)
▶️ Answer/Explanation
Frequency is defined as the number of complete waves (crests) passing a point per second.
Counting the number of crests passing in 30 seconds and dividing by 30 gives exactly this value.
Amplitude, wavelength and speed all require additional measurements (such as distance) that were not given here.
✅ Answer: (B)
Counting the number of crests passing in 30 seconds and dividing by 30 gives exactly this value.
Amplitude, wavelength and speed all require additional measurements (such as distance) that were not given here.
✅ Answer: (B)
▶️ Answer/Explanation
Refractive index is calculated using \(n = \frac{\sin(\text{angle of incidence})}{\sin(\text{angle of refraction})}\).
Substituting the given angles: \(n = \frac{\sin 70°}{\sin 35°} = \frac{0.940}{0.574}\).
This gives \(n \approx 2.4\).
✅ Answer: (C)
Substituting the given angles: \(n = \frac{\sin 70°}{\sin 35°} = \frac{0.940}{0.574}\).
This gives \(n \approx 2.4\).
✅ Answer: (C)
▶️ Answer/Explanation
A quieter sound has a smaller amplitude, while a higher pitch has a shorter wavelength (more oscillations in the same time, i.e. a higher frequency).
The graph needed must show a smaller peak height than the original combined with more wave cycles squeezed into the same time period.
Graph D is the only one drawn to scale showing both a reduced amplitude and an increased frequency compared with the original.
✅ Answer: (D)
The graph needed must show a smaller peak height than the original combined with more wave cycles squeezed into the same time period.
Graph D is the only one drawn to scale showing both a reduced amplitude and an increased frequency compared with the original.
✅ Answer: (D)
▶️ Answer/Explanation
Resistance is directly proportional to length and inversely proportional to cross-sectional area: \(R \propto \frac{l}{X}\).
Doubling the length doubles resistance, and halving the area also doubles resistance, so doing both multiplies resistance by \(2 \times 2 = 4\).
This matches a wire of length 2l and cross-sectional area ½X, giving resistance 4R.
✅ Answer: (B)
Doubling the length doubles resistance, and halving the area also doubles resistance, so doing both multiplies resistance by \(2 \times 2 = 4\).
This matches a wire of length 2l and cross-sectional area ½X, giving resistance 4R.
✅ Answer: (B)
▶️ Answer/Explanation
Electrical power is calculated as \(P = VI = 3.0 \times 3.0 = 9.0\ \text{W}\).
Time must be converted to seconds: \(3.0\ \text{minutes} = 180\ \text{s}\).
Energy transferred is \(E = Pt = 9.0 \times 180 = 1620\ \text{J}\).
✅ Answer: (D)
Time must be converted to seconds: \(3.0\ \text{minutes} = 180\ \text{s}\).
Energy transferred is \(E = Pt = 9.0 \times 180 = 1620\ \text{J}\).
✅ Answer: (D)
▶️ Answer/Explanation
A fuse protects a circuit by melting and breaking the circuit if the current becomes dangerously high, preventing overheating and fire — it does not maintain a constant current.
The fuse rating must be just above the normal operating current of 10 A, so a 13 A fuse is suitable (a 9 A fuse would blow immediately during normal use).
This matches “protects from overheating” with a 13 A rating.
✅ Answer: (D)
The fuse rating must be just above the normal operating current of 10 A, so a 13 A fuse is suitable (a 9 A fuse would blow immediately during normal use).
This matches “protects from overheating” with a 13 A rating.
✅ Answer: (D)
▶️ Answer/Explanation
Magnetic field lines run from the north pole to the south pole, so with N on the left, the field points to the right.
Using the given current direction together with the field direction and applying the left-hand (motor) rule for force, field and current.
This combination produces a resultant force acting downwards on the wire.
✅ Answer: (C)
Using the given current direction together with the field direction and applying the left-hand (motor) rule for force, field and current.
This combination produces a resultant force acting downwards on the wire.
✅ Answer: (C)
▶️ Answer/Explanation
A magnetic field only exerts a force on a moving charged particle.
Gamma rays are electromagnetic radiation, not particles, and carry no electric charge.
With no charge, gamma rays experience no magnetic force and travel straight through the field undeflected.
✅ Answer: (D)
Gamma rays are electromagnetic radiation, not particles, and carry no electric charge.
With no charge, gamma rays experience no magnetic force and travel straight through the field undeflected.
✅ Answer: (D)