The command word is the first thing to read in a question: it tells you what kind of answer earns the marks. Here is every command word the International GCSE Biology papers use, grouped by the job it asks for. Open “Show a model answer” after you have tried each one.
Short answers. A word, a phrase or one sentence, with no reason needed.
Three words for the same job: recall a fact.
How to answer: One short, exact answer per mark. No explanation.
Model answer: Carbon dioxide.
Common slip: Writing a paragraph around the fact, or giving two answers when one is wrong: a wrong second answer can cancel the right one.
Practise: Module 1: Command wordsGive the meaning of a term.
How to answer: A definition in your own words that would make sense to someone who has never met the term.
Model answer: A protein that acts as a biological catalyst, speeding up chemical reactions without being used up.
Common slip: Using the word to define itself, such as “osmosis is when osmosis happens to water”.
Pick out the key information from something the question gives you: a diagram, table, graph or passage.
How to answer: Look in the stimulus first. The answer is usually there.
Model answer: Palisade mesophyll.
Common slip: Answering from memory and ignoring what is actually labelled or written.
Put names, arrows or units onto a diagram or table you have been given.
How to answer: Write on the stimulus itself, with label lines that touch the right part.
Model answer: Time / minutes (or s, whichever matches the readings).
Common slip: A label line that stops short of the structure or points between two parts.
Fill in the gaps in a table, diagram, word equation or sentence.
How to answer: Match the style of what is already there: same units, same number of decimal places.
Model answer: Carbon dioxide + water.
Common slip: Leaving one gap empty, or changing the format the table already uses.
Longer answers, one creditable point per mark.
Give an account of what happens or what something is like. No reason is needed.
How to answer: For a graph: the overall trend, any change in the pattern, and values with units.
Model answer: The rate increases steadily up to about 40 units, then levels off at about 40 bubbles per minute.
Common slip: Giving the reason (“because light is a limiting factor”) instead of the pattern: that is Explain, not Describe.
Practise: Module 3: Data and graphsGive reasons: say why or how something happens.
How to answer: A because-so chain. Each link is a mark, so do not jump from the first idea to the last.
Model answer: Muscles respire faster to release more energy, so they need more oxygen and glucose and produce more carbon dioxide, so the heart beats faster to deliver more blood to the muscles.
Common slip: Describing what changes and stopping there, with no “because” or “so”.
Practise: Module 2: Long answersA statement has already been made. You only supply why.
How to answer: Go straight to the reason. Do not repeat the statement.
Model answer: Temperature affects the rate of enzyme activity, so keeping it the same (a control variable) means only the variable being tested changes the result.
Common slip: Restating the method (“to keep them at 35 °C”) instead of the reason for it.
Use what you know in a context you have not met before. More than one answer can earn the mark.
How to answer: Name the biology you are applying, then apply it to the new situation.
Model answer: A smaller surface area means less water is lost by transpiration, which helps the plant survive where water is scarce.
Common slip: Writing “I don’t know this plant” and leaving it blank. Suggest rewards a sensible use of a known idea.
Practise: Module 1: Command wordsGive evidence that supports a statement, or supports an answer you gave earlier.
How to answer: Point to the data or the biology that backs the claim, then say how it backs it.
Model answer: Enzyme B’s highest rate (illustrative: 9.2 units) is at pH 2, and the rate falls as the pH rises towards neutral.
Common slip: Repeating the claim more strongly instead of giving evidence for it.
Look at the data in detail, then use what you find to explain it.
How to answer: Two halves: quote what the data shows, then give the biology that causes it.
Model answer: The rate rises from 10 to 40 °C because molecules move faster and collide more often, then falls sharply above 40 °C because the enzyme’s active site changes shape and it is denatured.
Common slip: Doing only one half: data with no reasons, or reasons with no data.
Practise: Module 3: Data and graphsNumbers, graphs and diagrams. Working and units earn marks.
Work out a numerical answer, showing your working.
How to answer: Write the method, the substituted numbers, the answer and the unit.
Model answer: 18 ÷ 24 × 100 = 75%.
Common slip: A bare number with no working and no unit. If it is wrong, there is nothing left to credit.
Practise: KS4 Maths ClinicGet an answer that has to come from numbers in the information given.
How to answer: Show where the numbers come from, for example a reading from the graph, and use them.
Model answer: Reading from the graph: 1.6 cm³ per hour at 20 °C (illustrative).
Common slip: Guessing a value without showing it came from the graph or table.
Practise: Module 3: Data and graphsFind an approximate value, from a diagram, from data, or by a rough calculation.
How to answer: Round sensibly, say how you got it, and give the unit.
Model answer: Area = 1000 m², so about 3 × 1000 = 3000 daisies.
Common slip: Spending time on an exact answer when a sensible approximation was asked for.
Practise: KS4 Maths ClinicProve a value or statement the question has given you.
How to answer: Every step of the working, ending with a value that matches (or rounds to) the one given.
Model answer: Magnification = image size ÷ real size = 40 ÷ 0.2 = 200, so about ×200.
Common slip: Writing just the given answer. The marks are for the working that reaches it.
Practise: KS4 Maths ClinicDraw a graph from data by marking points accurately on the grid, then add the line or curve of best fit.
How to answer: SLAPUK: a sensible scale, labelled axes with units, accurate points, and a smooth line or curve of best fit.
Model answer: Points within half a small square of the true values, axes labelled with units, a scale that uses more than half the grid, and a line of best fit.
Common slip: A scale that jumps unevenly, or one that uses less than half the grid.
Practise: Graph skillsA freehand drawing. For a graph: labelled axes and the shape of the line, but no scale.
How to answer: Get the shape and key features right: where it rises, peaks or levels off.
Model answer: Axes labelled rate and temperature. A curve rising gradually to a peak at the optimum, then falling steeply.
Common slip: Spending time on exact points: a sketch is about the shape.
Practise: Graph skillsProduce a diagram, with a ruler or freehand.
How to answer: Clear, single lines. Label it if asked. Use a ruler for straight lines and label lines.
Model answer: A labelled diagram: pondweed in a beaker of water, an upturned funnel over it, and a water-filled test tube or measuring cylinder over the funnel to collect the gas.
Common slip: Sketchy, shaded drawings with labels floating away from the parts they name.
Practise: Graph skillsSay what result you would expect.
How to answer: State the result. If there are marks for it, add a short reason.
Model answer: Its mass will decrease, because water leaves the cells by osmosis.
Common slip: Being vague (“it will change”). Say which way and, where you can, by roughly how much.
Reach a conclusion from the information you are given.
How to answer: Link the clue in the information to the conclusion: “The data shows … so …”.
Model answer: The mother. The son gets his only X chromosome from his mother, so she must carry the recessive allele.
Common slip: Giving the conclusion with no link back to the information that proves it.
The highest-mark questions. Both sides, then a decision, or a full plan.
Bring several pieces of information together to make a judgement.
How to answer: Use two or more points from the data or information, then say what they add up to.
Model answer: The fertilised plots had a higher mean yield (illustrative: 6.1 vs 4.8 tonnes per hectare), but there were only two plots of each, so the data supports the claim only weakly.
Common slip: Picking one number and stopping. A comment weighs more than one piece of information.
Explore an issue from all sides, reasoning about each.
How to answer: Name the issue, give points on each side with reasons, and keep it balanced.
Model answer: For: it is specific to the pest and leaves no chemical residues. Against: the organism released may feed on other species or become a pest itself, and it acts more slowly.
Common slip: Writing only the advantages, or only the disadvantages.
Practise: Module 1: Command wordsWeigh up strengths and weaknesses using evidence, then reach a supported judgement.
How to answer: For, against, then “Overall … because …”. The judgement is where many marks are.
Model answer: For: a higher temperature can increase the rate of photosynthesis, so the yield may rise. Against: the fuel costs money, and above the optimum the enzymes slow down. Overall it is worth it only if temperature is the limiting factor and the extra crop is worth more than the fuel.
Common slip: A list of points with no final judgement.
Practise: Module 1: Command wordsPlan an investigation (or invent a procedure) from ideas you already know.
How to answer: CORMMSS: what you Change, the Organism, Repeats, the two Measures, and the variables you keep the Same.
Model answer: Change the temperature (five water baths, 20 to 60 °C); same source of amylase; repeat each three times; measure the time until the starch is gone, testing a drop with iodine every 30 seconds; keep the same pH and the same volumes and concentrations of starch and amylase (control variables).
Common slip: Naming the variables but never saying how the result would be measured.
Practise: Plan an investigation (CORMMSS)Multiple-choice questions use the plain question words What, Why and Which. Read every option before you choose, and cross out the ones you can rule out.
Command words from the Pearson Edexcel International GCSE Biology (Modular) specification, Appendix 4: Command word taxonomy (Issue 2, September 2024). The meanings, methods and examples are ScholarLab’s own wording. Specification page.
