Which is the main energy source for an ecosystem?

In any food chain,an average of $10 \%$ of the food eaten is turned into the body mass of an organism and made available for the next level of consumers.

Which of the following are always at the second trophic level of food chains?

Select the mismatched pair in the following and correct it.
$(a)$ Biomagnification — Accumulation of chemicals at the successive trophic levels of a food chain
$(b)$ Ecosystem — Biotic components of environment
$(c)$ Aquarium — $A$ man-made ecosystem
$(d)$ Parasites — Organisms which obtain food from other living organisms

State with reason any two possible consequences of the elimination of decomposers from the Earth.

Which of the following is an example of biodegradable waste?