In an ecosystem, at which trophic level can a human consuming curd be placed?

Identify the mismatched pair from the given options.

Which of the following statements are correct?
$(a)$ Net primary productivity is available biomass for consumption to heterotrophs.
$(b)$ Secondary productivity is defined as the rate of formation of new organic matter by heterotrophs.
$(c)$ The annual net primary productivity of the ocean is greater than that of land.
$(d)$ Warm and moist environment favours decomposition.

Zooplanktonic forms are

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

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.