In the phosphorus cycle, phosphate becomes available by weathering of rocks first to

Carnivores are

Match the columns:

Column-$I$	Column-$II$
$(a)$ Decomposers	$(i)$ Bacteria
$(b)$ Primary productivity	$(ii)$ Consumers
$(c)$ Natural ecosystem	$(iii)$ Producers
$(d)$ Secondary productivity	$(iv)$ Forest

Which of the following contribute to the carbon cycle?

Match the following columns:

Column-$I$	Column-$II$
$(i)$ Ecosystem	$(P)$ Bacteria,Fungi
$(ii)$ Food chain	$(Q)$ Nutrient cycling
$(iii)$ Birds	$(R)$ Primary consumer
$(iv)$ Decomposers	$(S)$ Deer

Consider the following statements concerning food chains.
$I$. Removal of $80\; \%$ tigers from an area resulted in greatly increased growth of vegetation.
$II.$ Removal of most of the carnivores resulted in an increased population of deers.
$III.$ The length of food chains is generally limited to $3$ to $4$ trophic levels due to energy loss.
$IV.$ The length of food chains may vary from $2$ to $8$ trophic levels.
Which two of the above statements are correct?