An ecosystem is considered to be which type of system?

Name any two organisms which can occupy more than one trophic level in an ecosystem.

In a given ecosystem,the number of individuals in a species remains more or less constant over a period of time. The constancy of this number is maintained by:

Which of the following is a true example of a sedimentary cycle?

Succession is

The gradual and predictable changes in the species composition of a given area are called $..........$.