Understanding Biology Command Words
A command word tells a candidate what kind of thinking an answer must show, not just what topic it covers, so the same biological fact can be tested very differently depending on whether the question says name, describe, explain, or compare.
One-hour paid trial · Same-day reply
A command word decides the shape of the answer, not just the topic
Two questions can be about the exact same biological fact and still expect completely different answers, because the word instructing what to do with that fact is different. "Name the process by which water moves across a cell membrane" and "explain why water moves across a cell membrane" are both about osmosis, but the first expects a single term and the second expects a mechanism with a reason attached.
Reading the topic of a question without reading its command word gives an incomplete picture of what is actually being asked.
Because command words repeat across the whole syllabus, learning what each one expects is a one-time investment that applies to every topic afterwards, rather than something to work out fresh for every question.
Recall command words: name, state, list, define
| Command word | What the answer needs to show |
|---|---|
| Name / State | A specific term, structure, or fact, given directly without justification or elaboration. |
| List | Several separate items, each as a short term or phrase, without connecting sentences between them. |
| Define | The exact meaning of a term, usually as a short, precise statement rather than an example of the term in use. |
Description and explanation command words: describe, explain
"Describe" asks for what can be observed or what happens, the features of a structure, or the sequence of events in a process, without needing to give the reason behind it. A description of the stages of mitosis, for instance, states what happens at each stage without needing to justify why the cell behaves that way.
"Explain" asks for the reason behind a fact or observation, usually connecting a cause to its effect. Where "describe" would state that the stomata close, "explain" requires stating why they close and what that achieves for the plant.
Answering an "explain" question with only a description, or a "describe" question with an unrequested justification, both waste effort without earning marks for the other type of point that was actually asked for.
Comparison and evaluation command words: compare, differentiate, discuss, evaluate
"Compare" and "differentiate" both require two things to be considered together on the same aspect, not described one after the other in separate paragraphs, a similarity or difference has to be stated as a pairing, such as "structure A has feature X, while structure B has feature Y instead." A list of facts about one item followed by a separate list about the second item does not show a comparison even if both lists are correct.
"Discuss" and "evaluate" ask for more than one point of view or more than one factor to be weighed against each other, usually leading to a reasoned conclusion. These command words appear most often in Section B and C essay questions, where a one-sided answer that only presents a single angle does not fully meet what the word is asking for.
Applied and procedural command words: calculate, suggest, predict, classify
| Command word | What the answer needs to show |
|---|---|
| Calculate | A numerical answer with the working shown, using the correct formula and units. |
| Suggest | A reasonable, biologically sound idea for a scenario without a single fixed correct answer, rather than a memorised fact. |
| Predict | A reasoned outcome based on a pattern or principle already established in the question, not a guess made without reference to that pattern. |
| Classify | Items sorted into named groups according to a stated or identifiable criterion. |
How do command words map onto the three papers?
The same command words appear across all three papers, but each paper leans on a different part of the range. Paper 1's objective items mostly test recall and understanding, so the reasoning behind name, state and define is doing the work even when no command word is written on the item.
Paper 2 uses the full range: structured questions mix recall words with describe and explain, while the Section B and C essays lean on describe, explain, compare and discuss. Paper 3, the practical test, leans on the applied and procedural words, state the variable, tabulate, plot, suggest, predict, and explain a result, because it assesses science process skills rather than recall.
| Paper | Command words it leans on | Typical demand |
|---|---|---|
| Paper 1 | Recall and understanding (name, state, identify) | Recognise the correct option quickly |
| Paper 2 | Describe, explain, compare, discuss | Structured points and organised essays |
| Paper 3 | State, suggest, predict, explain a result | Apply process skills to an experiment |
Why do 'describe' and 'explain' cause the most lost marks?
The most common command-word error is answering an "explain" question with a description, stating what happens without giving the reason for it, or padding a "describe" answer with unrequested justification. Both leave marks on the table, because the marker is looking for the specific type of point the command word asked for.
The quickest self-check before moving on is to ask whether the answer actually contains the word "because" or its equivalent when the question said explain, and whether it is stating observable events, not reasons, when the question said describe.
- If the question says explain, check the answer gives a reason, not only what happens
- If the question says describe, check the answer states events or features, without forcing in a reason
- A "describe" answer that only lists causes, or an "explain" answer that only lists events, misses the point being marked
- The command word, not the topic, decides which of these two the answer needs
How can a student practise identifying the command word before answering?
Because the command word decides the shape of the answer, a small habit helps: underline it first, and restate in your head what it demands before writing anything. A student can practise this away from full questions by taking a set of past questions and sorting them by command word, all the "explain" questions together, all the "compare" questions together, which makes the pattern of what each word expects obvious across the whole syllabus at once.
After a few sessions, identifying the command word and the answer shape it requires becomes automatic, so the effort in the exam goes into the biology rather than into working out what the question wants.
Frequently asked questions
Why does identifying the command word matter before starting to answer?
Do all command words expect a written answer, or do some expect a diagram or number?
Does a command word being simple, like "name" or "state," mean the question itself is easy?
If a question has no obvious command word, how should it be read?
Related
One-hour paid trial · Same-day reply