Which of the following is not included in a freshwater ecosystem?

In the given figure,the various trophic levels are shown in the form of a pyramid. At which trophic level is maximum energy available and at which trophic level is the maximum number of organisms present?

An ecosystem includes

The environment is only regarded as a pristine collection of plants and animals.

Based on the medium of habitat,how many types of ecosystems are there?

Producers,consumers,and decomposers are which type of components of an ecosystem?