Apart from being a part of the food chain, predators play other important roles. Mention any two such roles supported by examples.

What is primary productivity? Why does it vary in different types of ecosystems?

State the relation between gross and net primary productivity.

How are productivity, gross productivity, net primary productivity and secondary productivity interrelated?

Describe the advantages for keeping the ecosystems healthy.

76.

Write what do phytophagous insects feed on

Explain the carbon cycle with the help of a simplified model. 

Explain how does:

(a) a primary succession start on a bare rock and reach a climax community?

(a) Explain primary productivity and the factors that influence it.

(b) Describe how do oxygen and chemical composition of detritus control decomposition?

With the help of a flow chart, show the phenomenon of biomagnification of DDT in an aquatic food chain.