Stick insects feed on privet leaves for 7 days. A researcher measures the dry mass of the leaves eaten, the dry mass of the faeces produced and the dry mass of the food still in the insects' guts at the end. The researcher also measures the increase in dry mass of the insects' body tissue, not counting the food in their guts.
Which statement about estimating the biomass transferred from the leaves to the stick insects is correct?
Use the increase in dry mass of the insects' body tissue, because this is new living material.
Use the dry mass of the leaves eaten, because all the leaf material eaten was transferred.
Add the dry mass of the food in the guts to the increase in body tissue, because both are inside the insects.
Add the dry mass of the faeces to the increase in body tissue, because both came from the leaves.
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.