9700/13 Biology May Jun 2011 Online Test | Cambridge AS and A Level MCQ

In a mangrove ecosystem, leaves from the grey mangrove plants fall into the water and sink to the mud below. They are then broken down by bacteria and fungi.
Invertebrates such as crabs, prawns, and molluscs live in the mud and feed on the dead leaves. The bullseye fish feeds on the invertebrates. Humans eat prawns, crabs and fish.
Herons and other wading birds live and breed in the mangroves. These birds feed on invertebrates and fish.
What…