The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
Biotic or ecological succession is the formation of a series of biotic communities at the same site over a period of time one after the other, till a stable climax community develops over the area. It occurs generally in bare areas. Primary succession takes place on a biological sterile soilless primary barren area. Secondary succession takes place in a recently denuded area which still contains a lot of organic debris, remains, and propagules of previous living organisms. The area has become barred due to the destruction of the community previously present. Thus, the correct t answer is option A.