Excessive aerenchyma is characteristic of

In the vast marine ecosystem, certain sea develop red colouration. This red colour is due to the presence of large population of which one of the following organisms?

A succulent xerophyte is

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