Question

In autogenic succession
A. Early and continued dominance of autotrophic organisms takes place like green plants.
B. Replacement of existing communities caused largely by any other external condition.
C. Early dominance of heterotrophs takes place such as bacteria, fungi and other animals.
D. Community itself modifies its own environment thus, causing its own replacement by new communities.
E. Starts with previously built up substrate with already existing matter.

Answer 1

Hint: Autogenic succession is an ecological succession that is driven by biotic factors within the ecosystem. The mechanism of autogenic succession is debated from a long time but the role of living beings shaping the progression of succession was realized early on.

Complete answer:
The plants themselves cause succession to occur by the various activities that occur in plants like captured by the leaves, water and nutrient uptake, nitrogen fixation, production of detritus and anthropogenic climate change. These phenomena lead to gradual ecological change in the plants. This leads to change in a particular spot of land which is known as a progression of inhabiting species.
The autogenic succession leads to improvement of site factors like increased organic matter but it also hinders the growth of the plant. There are basically two types of ecological succession that occurs based on the cause of succession which is allogenic and autogenic succession. Allogenic succession is the replacement of any existing community due to any external conditions not by any existing organisms. Autogenic example- Xerarch succession which takes place on the rock surface, lichen produces lichen acids. The acid produced by lichens withers the rock to form sand. Dead lichens add to soil and form a thin layer, lichens are then replaced by mosses.

Hence, the correct option is D. Community itself modifies its own environment thus, causing its own replacement by new communities.

Note: There are various other types of successions which lead to change in an organism on the basis of starting of succession which includes primary and secondary succession, on basis of community composition which are Autotrophic and heterotrophic succession, on basis of nature substratum which are hydrosere and xerosere and on basis of succession of microbes which is microsuccession.