Match the following and choose the correct option.

	Column I		Column II
(a)	Primary succession	(i)	Autotrophs
(b)	Climax community	(ii)	Community that has completed succession
(c)	Consumer	(iii)	Colonization of a new environment
(d)	Producer	(iv)	Animals

	(a)	(b)	(c)	(d)
1.	iii	ii	iv	i
2.	iii	i	iv	ii
3.	i	iii	ii	iv
4.	ii	iii	iv	i

Primary succession is an ecological succession in which the formation of a new area or colonization of new environment occurs.

Climax community is the community that has completed the succession, and will remain unchanged unless destroyed by events such as fire, earthquake, and so on.

Consumers are those organisms/animals that depend upon plants, directly or indirectly, for their source of food. They are also called heterotrophs. If they feed on the producers, they are called primary consumers.

Producers are the green plants that make their own food through the process of photosynthesis. Such plants are also known as autotrophs. Phytoplankton, algae and higher plants are some example of producers.