Which one of the following systems constitutes the primary producers?

Sometimes,due to biotic or abiotic factors,the climax community remains in a particular seral stage (pre-climax) without reaching the final climax. Do you agree with this statement? If yes,provide a suitable example.

Succession is

In an ecosystem with a simple food web or food chain,if a change occurs at any one trophic level,what characteristic will emerge?

Choose the odd one out with respect to the functional aspects of an ecosystem.

The food chain which begins with dead organic matter is called