The phosphates remain outside the natural cycle for a long time:

Which of the following statements is incorrect regarding the phosphorus cycle?

In a food chain of a grassland ecosystem,the top consumers are

Given below are four statements $(a-d)$ each with one or two blanks. Select the option which correctly fills the blanks in two statements.
$(a)$ Ecological succession is a ...$(i)$... and fairly predictable change in the ...$(ii)$... of a given area.
$(b)$ In ecological succession,the entire sequence of communities that successively change in a given area is called ...$(i)$....
$(c)$ Primary succession occurs on ...$(i)$....
$(d)$ Secondary succession is ...$(i)$... than primary succession.

Consider the following statements about food chain:
$I.$ The transfer of energy from producers to top consumers through a series of organisms is called a food chain.
$II.$ $A$ food chain is always straight and proceeds in a progressive straight line.
$III.$ In a food chain,there is a unidirectional flow of energy from the sun to producers and subsequently to a series of different types of consumers.
Which of the statements given above are correct?

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