Which of the following ecosystems is both man-made and aquatic?

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.

The pioneer community established on a bare rock is:

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

Ecological succession is a

What will happen to an ecosystem if:
$(a)$ All producers are removed;
$(b)$ All organisms of herbivore level are eliminated; and
$(c)$ All top carnivore population is removed?