The trophic level of S-bacteria and cyanobacteria is

Consider the following statements about food chain

$I.$ The transfer of energy from producers to top consumers through a series of organisms is called food chain

$II.$ A food chain is always straight and proceeds in a progressive straight line

$III.$ In a food chain, there is unidirectional flow of energy from sun to producers and subsequently to series of different types of consumers

Which of the statements given above are correct?

An ecosystem must have continuous external source of

The number of trophic levels in an ecosystem are limited. Comment.

The correct path of energy flow in an ecosystem is

How much percentage of absorbed water is used in photosynthesis