Which of the following is $NOT$ a major functional aspect of an ecosystem?

Which of the following has the largest population in a food chain?

Identify the mismatched pair from the given options.

Read the following statements carefully and answer the question given below:
$(1)$ $NPP = GPP - R$
$(2)$ Productivity of an ecosystem can be measured in $g/m^2/yr$ or $kcal/m^2/day$.
$(3)$ The total amount of energy produced by all producers in an ecosystem is called Gross Primary Productivity $(GPP)$.
$(4)$ The net primary productivity of the oceans is $55$ billion tons.
State the number of correct statements.

Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?

Identify the mismatched event from the following structures.