A young otter eats food containing 360 g of biomass. During the next day:
| Route by which biomass leaves the otter | Biomass lost in g |
|---|---|
| Faeces | 72 |
| Urea in urine | 18 |
| Carbon dioxide and water from respiration | 234 |
The remaining biomass is used to make new otter tissue.
Calculate the percentage of the biomass in the food that is used to make new otter tissue.
Explain why the biomass in the faeces and the biomass in the urea are lost from the otter by different processes.
103 exam-style questions on AQA GCSE Biology 7.4 Trophic levels in an ecosystem, covering 7.4.1 Trophic levels, 7.4.2 Pyramids of biomass, and 7.4.3 Transfer of biomass. Each one has a worked solution and a mark scheme showing where the marks go.