As insecticides reach at higher trophic level in food chain,their concentration:

Some of the nutrient cycles are labelled as below:
$I$. Sulphur cycle
$II$. Phosphorus cycle
$III$. Carbon cycle
$IV$. Nitrogen cycle
Of these,the sedimentary cycle is represented by:

Identify the likely organisms $(1), (2), (3)$ and $(4)$ in the food web shown below.

Snakes are included under which category in a food chain?

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

Match the following columns correctly:

Column-$I$	Column-$II$
$(i)$ Producers	$(P)$ Primary consumers
$(ii)$ Herbivores	$(Q)$ Net primary productivity
$(iii)$ Carnivores	$(R)$ Primary trophic level
$(iv)$ Top carnivores	$(S)$ Secondary productivity