Lesson aim: recognise what each of the ten most-used ESS command terms requires, and practise applying them to authentic exam-style questions.
These ten command terms account for roughly 94% of every question on IB-produced ESS papers. If you can recognise what each one is asking you to do and respond accordingly, you have nearly every Paper 1, Paper 2 and IA situation covered.
How to use this page: read the requirement, attempt the example question yourself, then reveal the mark scheme to check.
AO2 | typically 1 to 4 marks | the most common term in ESS papers
What this command term requires
Give a brief account or summary. You need to mention the key points without going into full detail or full reasoning. Think of it as the headline version: the main features, in order, with no extended explanation.
A good Outline answer is short, structured, and covers the essential points. A common pitfall is going too deep (which wastes time) or being too vague (which loses marks).
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Try this question (4 marks)
Ecological efficiency is typically between 5% and 20% for most ecosystems. Outline why efficiency varies between ecosystems and why it is never 100%.
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