Which of the following is a man-made ecosystem?

Biogeochemical cycles can be traced in

The changes that occur in successive seral stages to reach a climax community are:
$I.$ Changes in the diversity of species of organisms.
$II.$ Increase in the number of species and organisms.
$III.$ Increase in the total biomass.
Choose the correct option.

In hydrarch succession,the reed swamp stage is preceded by

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?

Choose the incorrect sentence from the following.