Find out the correct order of succession levels in xerarch.

Fill in the blanks.
$(a)$ Plants are called as . . . . . . because they fix carbon dioxide.
$(b)$ In an ecosystem dominated by trees,the pyramid (of numbers) is . . . . . . type.
$(c)$ In aquatic ecosystems,the limiting factor for the productivity is . . . . . . .
$(d)$ Common detritivores in our ecosystem are . . . . . . .
$(e)$ The major reservoir of carbon on earth is . . . . . . .

In the dry weight of living beings,$A$ $\%$ carbon is present. In the oceans,$B$ $\%$ of the total global carbon is dissolved. The total amount of carbon in the atmosphere is $C$ $\%$ of the total global carbon. Identify the correct values for $A, B,$ and $C$.

Some of the stages in the hydrarch succession are labelled as:
$I.$ Marsh meadow stage
$II.$ Reed swamp stage
$III.$ Submerged plant stage
$IV.$ Phytoplankton stage
$V.$ Submerged free floating plant stage
Identify the choice that represents the correct sequence of these stages.

Trees $\rightarrow$ Birds $\rightarrow$ Lice $\rightarrow$ Bacteria. Thus,the food chain is:

Assertion $A$: As a result of evolution,plant species have migrated from aquatic habitats to terrestrial habitats.
Reason $R$: Plants have undergone developmental changes while passing through various stages of succession.
Which option is correct for Assertion $A$ and Reason $R$?