Maximum biomass and variable organisms are found in

If a lake is polluted by $DDT$,its highest concentration will be found in:

Choose the correct sequence of True $(T)$ and False $(F)$ statements:
$(1)$ 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 carnivores.
$(4)$ The amount of energy decreases at each successive trophic level.

$X-$ Atmospheric input of phosphorus through rainfall is much smaller than carbon input.
$Y-$ The exchange of phosphorus between organisms and the environment is negligible.

Which one of the following is not a functional unit of an ecosystem?

Grassland biome for its maintenance requires