(a(i))[2]
Explain how phytoplankton reduce carbon dioxide concentrations in the atmosphere.
(a(ii))[1]
Suggest the role of zooplankton in this ecosystem.
(a(iii))[2]
State the names of two processes that release carbon dioxide into the atmosphere.
(a(iv))[3]
Describe the effect on the environment of extra carbon dioxide in the atmosphere.
(b(i))[1]
On Fig. 6.2, mark the trophic level that contains herbivores.
(b(ii))[3]
Explain why pyramids of energy usually contain fewer than five trophic levels.
(b(iii))[2]
State two advantages of using a pyramid of energy instead of a pyramid of biomass to represent a food chain.
(c(i))[2]
State what is meant by the term sustainable resource.
(c(ii))[2]
Explain one way that fishing can be managed to conserve fish stocks.