Shore crabs feed on mussels with hard shells and on soft-bodied ragworms. Biomass is transferred less efficiently when the shore crabs eat mussels.
Which statement explains this?
The shells cause more of the mussel biomass to be used to keep the shore crabs warm
The shells cause more of the mussel biomass to be left uneaten by the shore crabs
The shells cause more of the mussel biomass to be lost as urea in urine by the shore crabs
The shells cause more of the mussel biomass to be egested as faeces by the shore crabs
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.