Why State, Describe and Explain cause confusion

State, Describe and Explain are the most common command words in IGCSE exams. They require different response types, but many students treat them the same. Examiner reports for Cambridge and Edexcel regularly note that candidates:

• Write long explanations when asked to State (wasting time)
• Give reasons when asked to Describe (doing extra, uncredited work)
• Give only a description when asked to Explain (missing the “why” that earns marks)

Getting these three right can make a big difference to your score.

State: short and direct

What it means

• Cambridge: Express in clear terms
• Edexcel: Recall one or more pieces of information

What to do

Give a brief, direct answer. No explanation, no “because”, no development. One mark usually means one clear point.

Examples

Question	Good answer	Too much
State which organ excretes urea.	The kidney.	The kidney excretes urea because it filters the blood and removes waste products…
State one factor that affects the rate of diffusion.	Concentration gradient.	Concentration gradient—the steeper the gradient, the faster the rate because…
State the chemical formula of methane.	CH₄	CH₄, which is an alkane and the simplest hydrocarbon…

Common mistake

Writing a paragraph when a word or short phrase is enough. You will not get extra marks, and you lose time.

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Describe: what and how, not why

What it means

• Cambridge: State the points of a topic / give characteristics and main features
• Edexcel: Give an account of something, or link facts, information, events or processes in a logical order

What to do

Give an account of what something is or what happens. Include features, steps or characteristics. You do not need to explain causes or reasons.

Examples

Question	Good answer	Wrong type
Describe the process of osmosis.	Water moves from a dilute solution to a concentrated solution through a partially permeable membrane.	Water moves because the concentration gradient causes water molecules to diffuse… (that’s Explain)
Describe the structure of a villus.	Finger-like projection; thin walls; network of capillaries; lacteal.	It has a large surface area because… (that’s Explain)
Describe what happens when we inhale.	Ribs move up and out; diaphragm contracts and flattens; volume of thorax increases; air enters.	This happens because the pressure drops… (that’s Explain)

Common mistake

Including reasons (“because”, “in order to”, “so that”) when only a description is asked. That extra content is not credited and uses time.

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Explain: why and how, with reasons

What it means

• Cambridge: Set out purposes or reasons / make the relationships between things clear / say why and/or how and support with relevant evidence
• Edexcel: Say how or why something happens; “because” will be an important part of your answer

What to do

Give reasons and links. Use “because”. Show cause and effect. Connect ideas. The examiner is looking for the “why” or “how”.

Examples

Question	Good answer	Too weak
Explain why enzymes work best at their optimum temperature.	At low temperatures, molecules move slowly so fewer collisions occur. At high temperatures, the enzyme denatures so the active site changes shape and the substrate no longer fits.	Enzymes work best at a certain temperature. (Description only; no “why”)
Explain why the villus has a large surface area.	The large surface area increases the rate of absorption because more molecules can diffuse across the membrane at once.	The villus has finger-like projections. (Description; no link to function)
Explain why the rate of diffusion increases when the concentration gradient is steeper.	A steeper gradient means a bigger difference in concentration, so there are more molecules moving from high to low concentration per unit time.	Diffusion is faster. (No mechanism)

Common mistake

Stopping at what happens, without saying why or how. Use “because” and show the link between cause and effect.

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Quick comparison

Command word	Length	Focus	”Because”?
State	Short	Recall or identify	No
Describe	Medium	What / how it looks or happens	No
Explain	Longer	Why / how it works	Yes

Mark allocation as a guide

• 1 mark → often State or Identify
• 2–3 marks → often Describe (several points) or Explain (several linked points)
• 4+ marks → Explain or Discuss (developed explanation or argument)

Use the mark allocation to check you are writing the right amount.

How Tutopiya helps

Tutopiya tutors use past papers and mark schemes to practise matching your answers to the command word. Explore IGCSE resources or book a free trial.

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Based on Cambridge International and Pearson Edexcel command word definitions. Check your syllabus or specification for subject-specific guidance.