Succession on a secondary bare area is known as:

Phosphorus of the ocean becomes available to land plants due to:

Identify the possible link '$M$' in the following food chain.
Plant $\rightarrow$ Insect $\rightarrow$ $M$ $\rightarrow$ Snake $\rightarrow$ Eagle

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

The given food web contains some missing organisms $A, B, C$ and $D$. Identify these organisms and select the correct answer.

How many statements are correct?
$(a)$ Some animals like cockroaches,crows,etc.,are omnivores.
$(b)$ Detritus food chain $(DFC)$ begins with dead organic matter.
$(c)$ Each trophic level has a certain mass of living material at a particular time called as standing crop.
$(d)$ Species composition and stratification are two main structural features of an ecosystem.