The intermediate developmental stages in the ecological succession is called

The correct answer is A. sere.

A sere is a series of communities that develop in a particular area in a more or less predictable order, until a stable community called a climax community is reached. The process of succession is the gradual change in the composition of a community over time.

B. Ecesis is the initial colonization of an area by living organisms.
C. Climax community is a stable community that is in equilibrium with its environment.
D. Nudation is the process of exposing bare rock or soil to the environment.