Choose correct answer.

$(1)$ Zooplanktons are primary producers in an aquatic ecosystem.

$(2)$ Decomposition is largely an oxygen requiring process.

$(3)$ In a natural ecosystem, fishes, wolf, etc. are carnivore.

$(4)$ The amount of energy decreases in each successive trophic level.

Consider the following four statements $(A-D)$ and select the correct option stating which ones are true $(T)$ and
which ones are false $(F)$.
Statements :
$(A)$ Vertical distribution of different species occupying different levels in a community is called stratification.
$(B)$ Net primary productivity minus respiration losses is the gross primary productivity.
$(C)$ Rate of biomass production is called decomposition
$(D)$ Annual net primary productivity of oceans is $55$ billion tons

The order of organism in an aquatic food chain is

Definitions / Explanation :

$(i)$ Saprotrophs

$(ii)$ Trophic level

Which of the following organisms convert plant matter into animal matter?

Fill in the trophic levels $(1, 2, 3$ and $4)$ in the boxes provided in the figure.