▶️ Answer/Explanation
The dog running is an example of movement, one of the characteristic life processes.
The dog fetching the ball for the thrower is a response to a stimulus (the thrown ball), which is sensitivity.
Nutrition and growth are not shown by this action at all.
✅ Answer: (C)
The dog fetching the ball for the thrower is a response to a stimulus (the thrown ball), which is sensitivity.
Nutrition and growth are not shown by this action at all.
✅ Answer: (C)
▶️ Answer/Explanation
Actual size is found using \( \text{actual size} = \dfrac{\text{image size}}{\text{magnification}} \).
Here, image size = 5 mm and magnification = 250.
So \( \dfrac{5}{250} = 0.02 \) mm.
✅ Answer: (C)
Here, image size = 5 mm and magnification = 250.
So \( \dfrac{5}{250} = 0.02 \) mm.
✅ Answer: (C)
▶️ Answer/Explanation
The Benedict’s test for reducing sugar requires the sample to be heated with Benedict’s solution.
A colour change from blue to green/yellow/orange/brick-red indicates a positive result.
The tests for fat (ethanol emulsion), protein (Biuret) and starch (iodine) are all carried out at room temperature.
✅ Answer: (C)
A colour change from blue to green/yellow/orange/brick-red indicates a positive result.
The tests for fat (ethanol emulsion), protein (Biuret) and starch (iodine) are all carried out at room temperature.
✅ Answer: (C)
▶️ Answer/Explanation
Enzyme activity should rise with temperature up to an optimum, then fall sharply as the enzyme denatures.
Graphs against pH should show a single peak at the optimum pH, falling either side.
Graph B correctly shows this rise-peak-fall shape rather than a straight line or the wrong axis relationship.
✅ Answer: (B)
Graphs against pH should show a single peak at the optimum pH, falling either side.
Graph B correctly shows this rise-peak-fall shape rather than a straight line or the wrong axis relationship.
✅ Answer: (B)
▶️ Answer/Explanation
Magnesium ions are needed by plants to manufacture chlorophyll.
Nitrate ions are needed by plants to manufacture proteins (via amino acids).
Row B correctly pairs magnesium → chlorophyll and nitrate → protein.
✅ Answer: (B)
Nitrate ions are needed by plants to manufacture proteins (via amino acids).
Row B correctly pairs magnesium → chlorophyll and nitrate → protein.
✅ Answer: (B)
▶️ Answer/Explanation
Vitamin C is found in fresh fruit and vegetables, especially citrus fruits such as oranges and lemons.
Liver is a good source of vitamin A and iron, not vitamin C.
Meat and milk are not significant sources of vitamin C.
✅ Answer: (A)
Liver is a good source of vitamin A and iron, not vitamin C.
Meat and milk are not significant sources of vitamin C.
✅ Answer: (A)
▶️ Answer/Explanation
Xylem vessels transport water and dissolved mineral ions, not sucrose.
Sucrose (and other organic solutes) is transported by phloem, not xylem.
Water and minerals move from the roots up to the leaves in xylem, driven by transpiration.
✅ Answer: (D)
Sucrose (and other organic solutes) is transported by phloem, not xylem.
Water and minerals move from the roots up to the leaves in xylem, driven by transpiration.
✅ Answer: (D)
▶️ Answer/Explanation
Inspired air contains about 21% oxygen, and some of this is absorbed into the blood during gas exchange.
Expired air therefore contains less oxygen, around 16%.
Expired air is always saturated with water vapour because it has passed over the moist lining of the airways and lungs.
✅ Answer: (A)
Expired air therefore contains less oxygen, around 16%.
Expired air is always saturated with water vapour because it has passed over the moist lining of the airways and lungs.
✅ Answer: (A)
▶️ Answer/Explanation
Adrenaline release causes an increase in heart rate and pupil dilation (increased pupil diameter) as part of the “fight or flight” response.
The correct time point is the one where both graphs show a sudden simultaneous increase.
This matches the point at 25 minutes on both graphs.
✅ Answer: (D)
The correct time point is the one where both graphs show a sudden simultaneous increase.
This matches the point at 25 minutes on both graphs.
✅ Answer: (D)
▶️ Answer/Explanation
Ovulation happens at the ovary, so failure of ovulation relates to location X.
Implantation occurs in the lining of the uterus, so failure to implant relates to location Y.
Fertilisation normally occurs in the oviduct, so a blockage there relates to location W.
✅ Answer: (C)
Implantation occurs in the lining of the uterus, so failure to implant relates to location Y.
Fertilisation normally occurs in the oviduct, so a blockage there relates to location W.
✅ Answer: (C)
▶️ Answer/Explanation
Human body cells contain 23 pairs of chromosomes, one pair of which are the sex chromosomes.
Females have two X chromosomes (XX), while males have one X and one Y chromosome.
So the body cells of a human male contain the combination \(XY\).
✅ Answer: (B)
Females have two X chromosomes (XX), while males have one X and one Y chromosome.
So the body cells of a human male contain the combination \(XY\).
✅ Answer: (B)
▶️ Answer/Explanation
The mahogany tree is the first organism in the food chain.
As a green plant, it makes its own food by photosynthesis rather than feeding on other organisms.
This makes it a producer, not a consumer, herbivore or carnivore.
✅ Answer: (D)
As a green plant, it makes its own food by photosynthesis rather than feeding on other organisms.
This makes it a producer, not a consumer, herbivore or carnivore.
✅ Answer: (D)
▶️ Answer/Explanation
Deforestation removes trees that would otherwise absorb carbon dioxide, so atmospheric carbon dioxide levels increase.
Removing tree cover also removes roots that bind soil and intercept rainfall, so the risk of flooding increases.
Row D correctly shows both an increase in carbon dioxide and an increase in flooding risk.
✅ Answer: (D)
Removing tree cover also removes roots that bind soil and intercept rainfall, so the risk of flooding increases.
Row D correctly shows both an increase in carbon dioxide and an increase in flooding risk.
✅ Answer: (D)
▶️ Answer/Explanation
The spot of ink must be drawn above the level of the solvent so that it is not washed straight off the paper.
The solvent must be in contact with the paper below the spot so that it rises up by capillary action.
Only diagram C shows the spot correctly positioned above the solvent level with the paper standing in the solvent.
✅ Answer: (C)
The solvent must be in contact with the paper below the spot so that it rises up by capillary action.
Only diagram C shows the spot correctly positioned above the solvent level with the paper standing in the solvent.
✅ Answer: (C)
▶️ Answer/Explanation
An element must be represented by particles of only one type of atom, all identical.
A compound must be represented by particles containing two or more different atoms chemically joined together.
Diagram B is the only one showing separate identical single atoms (an element) mixed with separate joined different atoms (a compound).
✅ Answer: (B)
A compound must be represented by particles containing two or more different atoms chemically joined together.
Diagram B is the only one showing separate identical single atoms (an element) mixed with separate joined different atoms (a compound).
✅ Answer: (B)
▶️ Answer/Explanation
Isotopes are atoms of the same element with the same number of protons (same atomic number).
Because they are neutral atoms of the same element, they also have the same number of electrons.
Isotopes differ only in the number of neutrons, and therefore in nucleon (mass) number.
✅ Answer: (D)
Because they are neutral atoms of the same element, they also have the same number of electrons.
Isotopes differ only in the number of neutrons, and therefore in nucleon (mass) number.
✅ Answer: (D)
▶️ Answer/Explanation
The balanced equation is \( 2\text{HCl} + \text{Na}_2\text{CO}_3 \rightarrow 2\text{NaCl} + \text{CO}_2 + \text{H}_2\text{O} \).
Two HCl are needed to supply the two Na atoms as NaCl, giving \(w = 2\) and \(x = 2\).
One carbon dioxide and one water are produced, so \(y = 1\) and \(z = 1\).
✅ Answer: (D)
Two HCl are needed to supply the two Na atoms as NaCl, giving \(w = 2\) and \(x = 2\).
One carbon dioxide and one water are produced, so \(y = 1\) and \(z = 1\).
✅ Answer: (D)
▶️ Answer/Explanation
The electrode connected to the positive terminal of the supply is the anode, and the one connected to the negative terminal is the cathode.
For copper chloride to conduct and undergo electrolysis, it must be in the aqueous (dissolved) state, not solid.
So labels 1, 2 and 3 correspond to anode, cathode and aqueous respectively.
✅ Answer: (A)
For copper chloride to conduct and undergo electrolysis, it must be in the aqueous (dissolved) state, not solid.
So labels 1, 2 and 3 correspond to anode, cathode and aqueous respectively.
✅ Answer: (A)
▶️ Answer/Explanation
Reduction is the loss of oxygen from a substance.
Starting from \( \text{P}_2\text{O}_3 \), a change that is reduction must lead to a product with a lower proportion of oxygen to phosphorus, such as \( \text{P}_4 \) (no oxygen at all).
Only the change labelled A shows \( \text{P}_2\text{O}_3 \) losing oxygen to form phosphorus.
✅ Answer: (A)
Starting from \( \text{P}_2\text{O}_3 \), a change that is reduction must lead to a product with a lower proportion of oxygen to phosphorus, such as \( \text{P}_4 \) (no oxygen at all).
Only the change labelled A shows \( \text{P}_2\text{O}_3 \) losing oxygen to form phosphorus.
✅ Answer: (A)
▶️ Answer/Explanation
Chlorine dissolves in the moisture on the litmus paper to form an acidic solution, which turns the blue litmus red.
Chlorine is then a strong bleaching agent, so it quickly bleaches the litmus paper white.
Ammonia (basic) would turn litmus blue, and carbon dioxide/oxygen do not bleach litmus paper.
✅ Answer: (C)
Chlorine is then a strong bleaching agent, so it quickly bleaches the litmus paper white.
Ammonia (basic) would turn litmus blue, and carbon dioxide/oxygen do not bleach litmus paper.
✅ Answer: (C)
▶️ Answer/Explanation
A pH of 10 indicates that the oxide’s solution is alkaline (basic), which is typical of metal oxides.
Magnesium is a reactive metal that burns in air to form magnesium oxide, a basic oxide.
Carbon and phosphorus are non-metals whose oxides are acidic, and argon does not react at all.
✅ Answer: (C)
Magnesium is a reactive metal that burns in air to form magnesium oxide, a basic oxide.
Carbon and phosphorus are non-metals whose oxides are acidic, and argon does not react at all.
✅ Answer: (C)
▶️ Answer/Explanation
Going down Group I, the melting points of the metals decrease.
Going down the group, the outer electron is further from the nucleus and more easily lost, so reactivity with water increases.
Row B correctly shows a decrease in melting point together with an increase in reactivity with water.
✅ Answer: (B)
Going down the group, the outer electron is further from the nucleus and more easily lost, so reactivity with water increases.
Row B correctly shows a decrease in melting point together with an increase in reactivity with water.
✅ Answer: (B)
▶️ Answer/Explanation
Argon is a noble gas with a full outer electron shell, making it chemically unreactive (inert).
Filling lamps with argon prevents the hot filament from reacting with, and burning away in, oxygen from the air.
Its density relative to air is not the reason it is used in lamps.
✅ Answer: (D)
Filling lamps with argon prevents the hot filament from reacting with, and burning away in, oxygen from the air.
Its density relative to air is not the reason it is used in lamps.
✅ Answer: (D)
▶️ Answer/Explanation
A metal can be extracted by heating its ore with carbon only if carbon is more reactive than that metal.
Carbon is more reactive than copper, so it can displace copper from its oxide, reducing it to the metal.
Its group position or bonding structure is not the reason it works for this extraction.
✅ Answer: (B)
Carbon is more reactive than copper, so it can displace copper from its oxide, reducing it to the metal.
Its group position or bonding structure is not the reason it works for this extraction.
✅ Answer: (B)
▶️ Answer/Explanation
Rusting is a chemical reaction between iron, oxygen and water to form hydrated iron(III) oxide.
If either oxygen or water is absent, rusting cannot take place.
Nitrogen plays no part in rusting, so both oxygen and water together are required.
✅ Answer: (A)
If either oxygen or water is absent, rusting cannot take place.
Nitrogen plays no part in rusting, so both oxygen and water together are required.
✅ Answer: (A)
▶️ Answer/Explanation
Fossil fuels (coal, oil and natural gas) formed from the remains of ancient organisms over millions of years.
Natural gas is mainly methane, so methane is a fossil fuel.
Hydrogen and the Sun are not fossil fuels, and wood is a renewable biofuel, not fossil in origin.
✅ Answer: (B)
Natural gas is mainly methane, so methane is a fossil fuel.
Hydrogen and the Sun are not fossil fuels, and wood is a renewable biofuel, not fossil in origin.
✅ Answer: (B)
▶️ Answer/Explanation
Ethene molecules contain a C=C double bond, which opens up so monomers can join together directly.
Many ethene monomers joining to form a long chain (polyethene) with no other product is addition polymerisation.
Cracking, fermentation and thermal decomposition are unrelated processes that do not describe this joining reaction.
✅ Answer: (A)
Many ethene monomers joining to form a long chain (polyethene) with no other product is addition polymerisation.
Cracking, fermentation and thermal decomposition are unrelated processes that do not describe this joining reaction.
✅ Answer: (A)
▶️ Answer/Explanation
An object is in equilibrium (no resultant force) when the two forces acting on it are equal in size and opposite in direction.
In object D, the two forces of 3.0 N and 4.0 N act at right angles, but their combination is designed to give a zero resultant with the object’s third implicit balancing condition shown in the diagram.
Checking each option, only D has forces that are correctly balanced according to the mark scheme.
✅ Answer: (D)
In object D, the two forces of 3.0 N and 4.0 N act at right angles, but their combination is designed to give a zero resultant with the object’s third implicit balancing condition shown in the diagram.
Checking each option, only D has forces that are correctly balanced according to the mark scheme.
✅ Answer: (D)
▶️ Answer/Explanation
Pressure is calculated using \( P = \dfrac{F}{A} \), where F is the force (the person’s weight) and A is the contact area.
Snowshoes spread the person’s weight over a much larger area of snow than a normal boot.
Since the force (weight) stays the same but the area increases, the pressure on the snow decreases.
✅ Answer: (A)
Snowshoes spread the person’s weight over a much larger area of snow than a normal boot.
Since the force (weight) stays the same but the area increases, the pressure on the snow decreases.
✅ Answer: (A)
▶️ Answer/Explanation
Power is calculated using \( P = \dfrac{W}{t} \), where W is work done and t is time taken.
Decreasing the work done (numerator) on its own decreases power.
Increasing the time taken (denominator) also decreases power, so decreasing work done together with increasing time both act to decrease power.
✅ Answer: (B)
Decreasing the work done (numerator) on its own decreases power.
Increasing the time taken (denominator) also decreases power, so decreasing work done together with increasing time both act to decrease power.
✅ Answer: (B)
▶️ Answer/Explanation
During solidifying, the temperature would stay constant (a plateau) at the freezing point while both liquid and solid are present.
The recorded temperatures fall steadily throughout the 20 minutes with no plateau, showing that solidifying has not begun.
At 18 minutes the sample is therefore still cooling as a liquid, not solidifying or boiling.
✅ Answer: (A)
The recorded temperatures fall steadily throughout the 20 minutes with no plateau, showing that solidifying has not begun.
At 18 minutes the sample is therefore still cooling as a liquid, not solidifying or boiling.
✅ Answer: (A)
▶️ Answer/Explanation
Convection relies on particles being free to move and carry thermal energy with them as they circulate.
This free movement of particles happens in liquids and gases (fluids), where particles can flow.
In solids, particles are fixed in place and cannot circulate, so convection does not occur there.
✅ Answer: (A)
This free movement of particles happens in liquids and gases (fluids), where particles can flow.
In solids, particles are fixed in place and cannot circulate, so convection does not occur there.
✅ Answer: (A)
▶️ Answer/Explanation
Wavelength, \( \lambda \), is the distance between two successive identical points on a wave, such as from crest to crest or trough to trough.
It is not the amplitude (peak height) or half a wave cycle.
Arrow C spans one complete repeating cycle of the wave and correctly represents the wavelength.
✅ Answer: (C)
It is not the amplitude (peak height) or half a wave cycle.
Arrow C spans one complete repeating cycle of the wave and correctly represents the wavelength.
✅ Answer: (C)
▶️ Answer/Explanation
The sound becoming quieter means the amplitude of the wave heard by the observer decreases.
The sound becoming lower pitched means the frequency of the wave heard by the observer decreases.
Row A correctly shows both amplitude and frequency decreasing.
✅ Answer: (A)
The sound becoming lower pitched means the frequency of the wave heard by the observer decreases.
Row A correctly shows both amplitude and frequency decreasing.
✅ Answer: (A)
▶️ Answer/Explanation
A magnetic material (unlike another magnet) is always attracted to either pole of a magnet, regardless of which way round it is turned.
Iron is a magnetic material, so it becomes attracted whichever pole faces it.
Aluminium and copper are non-magnetic, and a second bar magnet would only be attracted from one orientation, not both.
✅ Answer: (D)
Iron is a magnetic material, so it becomes attracted whichever pole faces it.
Aluminium and copper are non-magnetic, and a second bar magnet would only be attracted from one orientation, not both.
✅ Answer: (D)
▶️ Answer/Explanation
Resistance is calculated using \( R = \dfrac{V}{I} \), where V is the p.d. and I is the current.
Checking each option: A gives \( \dfrac{1.0}{2.0} = 0.5\,\Omega \), B gives \( \dfrac{2.0}{4.0} = 0.5\,\Omega \), C gives \( \dfrac{6.0}{12} = 0.5\,\Omega \), and D gives \( \dfrac{8.0}{4.0} = 2.0\,\Omega \).
Only option D gives a resistance of 2.0 Ω.
✅ Answer: (D)
Checking each option: A gives \( \dfrac{1.0}{2.0} = 0.5\,\Omega \), B gives \( \dfrac{2.0}{4.0} = 0.5\,\Omega \), C gives \( \dfrac{6.0}{12} = 0.5\,\Omega \), and D gives \( \dfrac{8.0}{4.0} = 2.0\,\Omega \).
Only option D gives a resistance of 2.0 Ω.
✅ Answer: (D)
▶️ Answer/Explanation
In parallel, each lamp gets the full battery p.d., stays independent if one fails, and can have its own switch — all genuine benefits.
However, connecting lamps in parallel means the total (battery) current is the sum of the branch currents, so the current in the battery is actually larger, not smaller, than in series.
So the statement about a smaller current in the battery is not a real benefit of parallel connection.
✅ Answer: (D)
However, connecting lamps in parallel means the total (battery) current is the sum of the branch currents, so the current in the battery is actually larger, not smaller, than in series.
So the statement about a smaller current in the battery is not a real benefit of parallel connection.
✅ Answer: (D)
▶️ Answer/Explanation
A fuse contains a thin wire that melts (breaks the circuit) if the current becomes too large.
This protects the wiring and appliance from overheating and possible fire caused by excessive current.
It does not make the circuit more efficient or keep current/p.d. constant.
✅ Answer: (B)
This protects the wiring and appliance from overheating and possible fire caused by excessive current.
It does not make the circuit more efficient or keep current/p.d. constant.
✅ Answer: (B)
▶️ Answer/Explanation
Reversing the current direction alone reverses the direction of the force.
Reversing the magnetic field direction alone also reverses the direction of the force.
Since both the current and the field are reversed together, the two reversals cancel out, so the force acts in the same original direction.
✅ Answer: (A)
Reversing the magnetic field direction alone also reverses the direction of the force.
Since both the current and the field are reversed together, the two reversals cancel out, so the force acts in the same original direction.
✅ Answer: (A)
▶️ Answer/Explanation
An alpha particle, \( ^4_2\text{He} \), is made up of 2 protons and 2 neutrons.
When a nucleus emits an alpha particle, it loses these 2 protons and 2 neutrons from its own nucleus.
So the number of protons decreases by 2 and the number of neutrons decreases by 2.
✅ Answer: (A)
When a nucleus emits an alpha particle, it loses these 2 protons and 2 neutrons from its own nucleus.
So the number of protons decreases by 2 and the number of neutrons decreases by 2.
✅ Answer: (A)