$15 \%$ can be taken as the average value for the amount of organic matter that is present at each step and reaches the next level of consumers.

Suggest one word for each of the following statements/definitions:
$(a)$ The physical and biological world where we live in
$(b)$ Each level of food chain where transfer of energy takes place
$(c)$ The physical factors like temperature,rainfall,wind and soil of an ecosystem
$(d)$ Organisms which depend on the producers either directly or indirectly for food

The structural and functional unit of the environment is known as $......$

Give the full form of $CFC$.

Which of the following is a top-level carnivore?

Write two characteristic features of energy flow in an ecosystem.