Identify the correct type of food chain.
Dead animal $\rightarrow$ Blow fly maggots $\rightarrow$ Common frog $\rightarrow$ Snake

Identify the organisms $I, II, III$ and $IV$ in the given food web.
$I$ | $II$ | $III$ | $IV$

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?

Maximum contribution of $O_2$ is from

The hydrological cycle comprises two overlapping cycles.

The first plants to reappear in a badly burned forest area will most probably be