A fruit juice factory puts waste fruit pulp into a small biogas generator. The generator is sealed at the start.
A fault allows air to enter during one interval.
| Interval | Oxygen concentration inside the generator (%) | Mean methane produced per day (litres) |
|---|---|---|
| Days 1–3 | 0.0 | 4.6 |
| Days 4–6 | 0.0 | 4.8 |
| Days 7–9 | 6.5 | 1.1 |
Use the data to explain during which interval the fault occurred and why the mean methane production changed.
83 exam-style questions on AQA GCSE Biology 7.2 Organisation of an ecosystem, covering 7.2.1 Levels of organisation, 7.2.2 How materials are cycled, 7.2.3 Decomposition, and 7.2.4 Impact of environmental change (HT only). Each one has a worked solution and a mark scheme showing where the marks go.