Which light is transmitted by water?

Which one of the following is a characteristic feature of a cropland ecosystem?

Identify the stage of hydrarch succession shown in the figure.

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

Organisms that consume milk and curd can be classified as ........

Read the following statements carefully and answer the question:
$(1)$ Pyramids of number and biomass can be upright or inverted in an ecosystem.
$(2)$ Phosphorus and sulfur are sedimentary cycles.
$(3)$ The largest reservoir of carbon on Earth is found in the oceans.
$(4)$ The structural and functional unit of ecology is the ecosystem.
Which of the above statements are correct?