Green plants constitute

Why are oceans least productive ?

How much percentage of absorbed water is used in photosynthesis

What will happen to an ecosystem if :

$(a)$ All producers are removed;

$(b)$ All organisms of herbivore level are eliminated; and

$(c)$ All top carnivore population is removed

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?

The organisms, which attack dead animals are