In the North East region of India, during the process of jhum cultivation, forests are cleared by burning and left for regrowth after a year of cultivation. How would you explain the regrowth of forest in ecological term ?

Some of the stages in the hydrarch are labelled as

$I.$ Marsh meadow stage

$II.$ Reed swamp stage

$III.$ Submerged plant stage

$IV.$ Phytoplankton stage

$V.$ Submerged free floating plant stage

Identify the choice that represents the correct sequence of these stages

The organisms which participate most actively in nitrogen cycle in nature are

Give differences : carbon cycle and phosphorus cycle.

Which one is the main source of minerals essential for man and other organisms