Which of the following is responsible for the high biomass in an aquatic ecosystem?

Which of the following characteristics can be observed in ecological succession?

Succession in a $6 \ m$ deep pond exhibits a sequence of

Identify the correct statements from the following:
$(1)$ Succession occurring in dry areas is called xerarch succession.
$(2)$ The stage where plants can survive in open conditions throughout the year is the herb stage.
$(3)$ Ecological succession leads to a decrease in the net primary productivity of the community.
$(4)$ Primary succession takes an average of $1000$ years to complete.

Identify the given food chain:
Grass $\rightarrow$ Grasshopper $\rightarrow$ Birds $\rightarrow$ Lion

Select the correct option for the following processes:
$P$ - Formation of organic components from inorganic components
$Q$ - Formation of inorganic components from organic components
Select the correct option for $P$ and $Q$.