Why do higher trophic levels in most ecosystems contain fewer organisms than lower trophic levels?

There is less energy in higher trophic levels.

Explanation:

With less energy at higher trophic levels, there are usually fewer organisms as well. Organisms tend to be larger in size at higher trophic levels!

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.

c. live where it’s cold and icy