Answer:
(i)
Polluted water causes a number of water-borne diseases like cholera, typhoid,
jaundice, diarrhoea, hepatitis and dysentery.
(ii) Presence of acids or alkalies in water destroys certain
microorganisms, which carry out the self-purification process in rivers.
(iii) Decrease in the amount of dissolved oxygen in the
water body adversely affects the life of aquatic organisms.
(iv) Change in water temperature disturbs the aquatic life as eggs and
larvae of various animals are badly affected by such changes.
Biological
nitrogen fixation means the conversion of atmospheric nitrogen into useful
nitrogen compounds by bacteria and algae. The bacteria present in the root
nodules of leguminous plants like Rhizobium as well as some blue green algae
help in the fixation of atmospheric nitrogen.
You need to login to perform this action.
You will be redirected in
3 sec
