The depletion of ozone layer in the upper atmosphere is mainly due to the emission of:

Which of the following limits the number of trophic levels in a food chain?

What percentage of sun's energy falling on the leaves of green plants is utilized by the plants in the process of photosynthesis and stored as chemical energy of food?

In an ecosystem, the ten per cent energy available for transfer from one trophic level to the next is in the form of:

The flow of energy in an ecosystem is always: