The entire sequence of communities that successively change in a particular area are called

1. A

   Ecological succession

   (a) Ecological succession. Succession is the process of community change; the entire sequence of those communities is not called succession itself.

2. B

   Sere

   (b) Sere. The full sequence of communities that successively occupy an area is a sere; each step is a seral stage, ending in a climax. That term is the official key.

3. C

   Community dynamics

   (c) Community dynamics. A loose phrase for change, not the technical name of the whole sequence.

4. D

   Pyramid of biomass

   (d) Pyramid of biomass. A standing-crop diagram, unrelated to the successional sequence.

Summary. Official key is (b). The entire successional sequence of communities in an area is a sere. Succession is the process; climax is the end stage.