Combined Science Paper 2 November 2023

Tap to enlarge

Answer this when you sit the paper.

1. AIt has a long tail and thin cytoplasm so that it can swim along the vessels.
2. BIt is biconcave in shape and has no nucleus, so it is filled with haemoglobin.
3. CIt has a large nucleus and many mitochondria in which the oxygen is stored for later.
4. DIt is covered in cilia and has a thick cell wall that protects the oxygen.

1. Aarises from the environment an individual grows in rather than from its genes.
2. Bdevelops gradually during an individual's lifetime in response to diet and habits.
3. Cproduces a continuous range of values spread evenly between two extremes.
4. Dsorts individuals into clear, distinct groups with no intermediate forms.

Answer this when you sit the paper.

1. Athe number of producers in a habitat sets a fixed limit on how many consumer species it can hold.
2. Benergy is lost as heat and in waste at each transfer, so too little is left for another level.
3. Cpredators at the top of a chain grow too large for any other organism to feed on them.
4. Ddecomposers break down the top consumers before they can pass their energy on further.

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Ahas a shorter incubation period and damages the nerves and tissues around the genitals, causing sores.
2. Bis spread by contaminated food and water rather than by any form of sexual contact.
3. Chas a longer incubation period and destroys white blood cells, weakening the immune system.
4. Dproduces blisters that heal within a few days and leaves the body's defences unharmed.

1. Aan increase in the baby's resistance to other infections after it is born.
2. Bblindness, paralysis, or death of the baby before it is born.
3. Ca permanent change in the baby's blood group and its inherited eye colour.
4. Dfaster growth of the baby's bones and an unusually high weight at birth.

Answer this when you sit the paper.

1. AA is alkaline (a base), because it turns red litmus blue, and B is acidic.
2. BA is acidic, because it turns red litmus blue, and B is alkaline (a base).
3. CBoth A and B are acidic, with B the stronger acid of the two substances.
4. DBoth A and B are alkaline, with A the stronger base of the two substances.

Answer this when you sit the paper.

1. ACaCO3 + 2HCl -> CaCl2 + H2 + CO2
2. BCaCO3 + 2HCl -> CaCl2 + CO2 + H2O
3. CCaCO3 + 2HCl -> Ca(OH)2 + H2 + CO2
4. DCaCO3 + HCl -> CaCl + CO2 + H2O

Answer this when you sit the paper.

1. Ais made up of carbon, hydrogen and oxygen joined together in a ring.
2. Bis made up of carbon and hydrogen, with no other element present.
3. Cis made up of hydrogen bonded to a metal such as sodium or calcium.
4. Dis made up of carbon joined to nitrogen in long unbranched chains.

Tap to enlarge

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Aholds more hydrogen atoms than any other hydrocarbon having the same chain length.
2. Bhas one carbon atom bonded to four different atoms or groups of atoms.
3. Chas at least one carbon to carbon double bond, so other atoms can add across it.
4. Dhas hydrogen atoms bonded to every carbon in a single unbranched chain.

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

Tap to enlarge

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Alike poles repel each other, while unlike poles attract each other.
2. Blike poles attract each other, while unlike poles repel each other.
3. Call magnetic poles attract one another with a force of the same size.
4. Dthe poles of a magnet lose their strength when they are brought close.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. AA motor produces electrical energy, and a generator produces kinetic energy.
2. BA motor produces heat energy, and a generator produces chemical energy.
3. CA motor produces kinetic energy, and a generator produces electrical energy.
4. DBoth a motor and a generator turn electrical energy into kinetic energy.

Answer this when you sit the paper.

1. Athe same amount of oxygen but much less nitrogen and water vapour.
2. Bless nitrogen, less carbon dioxide and a much lower temperature.
3. Cmore oxygen, less carbon dioxide and less water vapour than before.
4. Dless oxygen, more carbon dioxide and more water vapour than before.

Answer this when you sit the paper.

1. Aglucose -> lactic acid + carbon dioxide + energy
2. Bglucose + oxygen -> carbon dioxide + water + energy
3. Ccarbon dioxide + water -> glucose + oxygen + energy
4. Dglucose + carbon dioxide -> oxygen + water + energy

1. Athe glucose is not completely oxidised, so energy stays locked in the lactic acid or alcohol.
2. Bthe glucose is broken down so quickly that most of the energy escapes as heat at once.
3. Cno glucose is used at all, so the cell has to rely on the fat it has stored as its energy source.
4. Dthe oxygen that is present reacts with the glucose before the cell can make use of it.

1. ARespiration builds up carbohydrates, while photosynthesis breaks carbohydrates down.
2. BRespiration occurs in green plants alone, while photosynthesis occurs in every cell.
3. CRespiration releases energy from glucose, while photosynthesis stores energy in glucose.
4. DRespiration gives out oxygen, while photosynthesis gives out carbon dioxide as its waste gas.

Answer this when you sit the paper.

1. Apushes sugars down from the leaves into the roots for storage over winter.
2. Badds carbon dioxide to the air spaces inside the leaf ready for respiration.
3. Cpulls water and dissolved mineral salts up the plant and cools the leaves.
4. Dtraps sunlight in the leaves and turns it straight into chemical energy.

1. Aforms a waterproof layer that stops water evaporating through the leaf surface.
2. Bholds extra water inside the leaf which the plant draws on during a dry spell.
3. Copens the stomata wider so that water leaves the plant at a steadier rate.
4. Dreflects the sunlight falling on the leaf so that the inside of the leaf stays cool.

1. Atrap a layer of moist air next to the leaf, lowering the water diffusion gradient.
2. Bincrease the surface area of the leaf so that heat is lost faster into the air.
3. Cabsorb water vapour directly from the air and pass it back into the cells of the leaf.
4. Dcover the stomata so that carbon dioxide is taken in through the roots instead.

1. AIt moves into the root hair cells from the soil by osmosis, because the soil solution is the more concentrated of the two.
2. BIt moves into the root hair cells by active transport, because the salts drag water along behind them.
3. CIt stays exactly where it is, because osmosis stops once salts are dissolved in the soil water.
4. DIt moves out of the root hair cells into the soil by osmosis, because the soil solution is the more concentrated.

Answer this when you sit the paper.

1. Athe salt blocks the stomata in the leaves so that the guard cells cannot open.
2. Bthe leaves take in salt from the air, which makes their cuticle thicker than usual.
3. Cthe plant grows many more leaves in salty soil, which share the water between them.
4. Dless water reaches the leaves, so there is less water available to evaporate away.

Tap to enlarge

Answer this when you sit the paper.

1. AIt makes the diffusion distance short, so substances pass quickly to and from cells.
2. BIt lets the vessel store a large volume of blood until the body needs to use it.
3. CIt keeps plasma inside the vessel, so the blood does not lose any volume as it flows.
4. DIt makes the vessel wall strong enough to withstand the high pressure of blood from the heart.

1. Amore oxygen and less carbon dioxide.
2. Bless oxygen and less carbon dioxide.
3. Cless oxygen and more carbon dioxide.
4. Dmore oxygen and more carbon dioxide.

Answer this when you sit the paper.

1. Aright ventricle, pulmonary artery, lungs, pulmonary vein
2. Bright ventricle, aorta, lungs, vena cava
3. Cright ventricle, vena cava, lungs, pulmonary artery, aorta
4. Dleft ventricle, pulmonary vein, lungs, pulmonary artery

Answer this when you sit the paper.

1. Aloses both carbon dioxide and oxygen at the alveoli.
2. Bgains both carbon dioxide and oxygen at the alveoli.
3. Closes carbon dioxide and gains oxygen at the alveoli.
4. Dgains carbon dioxide and loses oxygen at the alveoli.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. AX is a noble gas, while Y belongs to Group I of the Periodic Table.
2. BX belongs to Group II, while Y belongs to Group VIII and is a metal.
3. CX belongs to Group VII, while Y belongs to Group II of the Periodic Table.
4. DX belongs to Group I, while Y has a full outer shell and is a noble gas.

1. Aa shiny metallic surface that conducts electricity well while the compound is still solid
2. Bthe ability to be drawn into a wire, because the ions slide over one another
3. Ca high melting point, because strong forces hold the oppositely charged ions together
4. Da low melting point, because weak forces act between its separate molecules

Answer this when you sit the paper.

1. Ahydrogen sulphide reacting with nitrogen from the air.
2. Bsulphur dioxide reacting with oxygen from the air.
3. Csulphur dioxide reacting with water vapour.
4. Dsulphur reacting with concentrated sulphuric acid.

1. Aabout 25 degrees Celsius, 1 atmosphere pressure and a nickel metal catalyst
2. Babout 450 degrees Celsius, 200 atmospheres pressure and a finely divided platinum catalyst
3. Cabout 450 degrees Celsius, 1 atmosphere pressure and a vanadium(V) oxide catalyst
4. Dabout 1500 degrees Celsius, 200 atmospheres pressure and an iron catalyst

1. Ais used up during the reaction, so fresh catalyst must be added at each stage.
2. Blowers the pressure inside the vessel, which increases the yield of the trioxide.
3. Cspeeds the reaction up without being used up, so the trioxide forms fast enough.
4. Draises the temperature of the reaction vessel so that more of the trioxide forms.

1. Aheated strongly so that the sulphur trioxide is driven off again.
2. Bmixed with more sulphur dioxide so that sulphurous acid is formed.
3. Cmixed with water to give concentrated sulphuric acid ready for sale.
4. Dcooled and filtered so that the vanadium(V) oxide catalyst is removed.

Answer this when you sit the paper.

1. Athe removal of oxygen, the removal of hydrogen, or the loss of electrons.
2. Bthe removal of oxygen, the addition of hydrogen, or the gain of electrons.
3. Cthe addition of oxygen, the addition of hydrogen, or the gain of electrons.
4. Dthe addition of oxygen, the removal of hydrogen, or the loss of electrons.

1. AFe2O3 + 3C -> 2Fe + 3CO
2. BFe2O3 + C -> 2Fe + CO2
3. C2Fe2O3 + 3C -> 4Fe + 3CO
4. DFe2O3 + 2C -> 2Fe + 2CO

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Aconducts heat so poorly that the handle of a hot pan stays cool to touch.
2. Bmelts at a low temperature, so worn pieces are easily reshaped at home.
3. Cis much lighter than every other metal, so it is very easy to carry about.
4. Dresists rusting and corrosion by acids, and is both strong and hard.

Answer this when you sit the paper.

1. Aplastic, because plastics contain free electrons that carry heat along a rod.
2. Bglass, because glass conducts heat better than a metal of the same size.
3. Cwood, because wood carries heat quickly from one end of a rod to the other.
4. Da metal, because metals are good conductors and carry heat along the rod.

1. Afar apart, so each particle travels a long way before it strikes another one.
2. Bmoving faster on average than the particles of a gas at the same temperature.
3. Cheld completely still, so they pass no vibration between one another at all.
4. Dclosely packed, so vibrations pass quickly from one particle to the next.

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Acan be created inside a machine, though once it has been created it cannot be destroyed.
2. Bcannot be created or destroyed, but can be changed from one form into another.
3. Cis destroyed each time it is changed from one form into a different form.
4. Dis created by a fuel as it burns and destroyed by friction as it acts.

1. Afriction between the tyre and the road surface turns kinetic energy into heat.
2. Bthe tyre gains heat from the engine, which is carried to it along the axle.
3. Cthe air inside the tyre is compressed by the weight of the car and then cools.
4. Dthe rubber absorbs sunlight from above, which it stores as chemical energy.

1. Athe total moment about the pivot is equal to the total weight resting on it.
2. Bthe sum of the clockwise moments equals the sum of the anticlockwise moments.
3. Cthe sum of the clockwise moments is greater than the sum of the anticlockwise ones.
4. Dthe clockwise and the anticlockwise moments each add up to zero newton metres.

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. Aa pair of scissors and a garden wheelbarrow
2. Ba car battery and a filament light bulb
3. Ca magnifying glass and a plane mirror
4. Da bicycle pump and a cordless electric hand drill

1. Athe load being lifted is heavier than the effort applied at the other end.
2. Ba machine gives out more energy than is put into it, and the extra is lost.
3. Cthe effort is applied further from the pivot than the load is placed.
4. Dsome of the work put in overcomes friction and lifts the lever itself.

1. Acopper contains free electrons that drift through it carrying charge, while polythene has none.
2. Bcopper is made of positive ions that move through it, while polythene is made of neutral atoms.
3. Cpolythene contains free electrons that carry charge, while copper holds its electrons tightly.
4. Dcopper is denser than polythene, and a denser material carries a current more easily.

Answer this when you sit the paper.

Answer this when you sit the paper.

1. AIt stays the same, because the other bulbs still carry the current between them.
2. BIt halves, because the current now divides itself between the remaining bulbs.
3. CIt falls to zero, because no current can flow round a circuit that is broken.
4. DIt rises sharply, because the current no longer has to pass through that bulb.

1. Achange the alternating mains supply into a direct current supply.
2. Bmelt and break the circuit when the current flowing becomes too large.
3. Cstore charge so that the appliance keeps running during a power cut.
4. Dincrease the current flowing so that the appliance works more quickly.

1. Atake hold of the person's bare hand at once and pull them clear quickly.
2. Bhold on to a metal water pipe for support while reaching out to them.
3. Cpour cold water over the person to cool the burns before pulling them clear.
4. Dswitch off the supply at the mains and stand on a dry insulating material.

1. Adirect current can be carried along metal wires, while alternating current travels through air.
2. Bdirect current flows in one direction only, while alternating current reverses regularly.
3. Cdirect current is measured in volts, while alternating current is measured in amperes.
4. Ddirect current reverses its direction regularly, while alternating current does not.