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

In a certain study conducted on the occurrence of $DDT$ along food chains in an ecosystem,the concentration of $DDT$ in grass was found to be $0.5\, ppm$ (parts per million),in sheep it was $2\, ppm$,and in man it was $10\, ppm$. Why was the concentration of $DDT$ maximum in the case of man?

The most important compound which accounts for almost $80\%$ of the total depletion of the ozone layer is $.........$

In an ecosystem,the $10 \%$ of energy available for transfer from one trophic level to the next is in the form of

At one trophic level,an average of $10 \%$ of the energy taken is turned into its own body and made available for the next level of consumers. What happens to the rest of $90 \%$ of the energy?

Organisms of a higher trophic level which feed on several types of organisms belonging to a lower trophic level constitute the