The diagram shows how a community will colonize bare rock, and then change over hundreds of years. n this example, what is the main cause of the changes that the community undergoes?
a
ecological succession, because each community promotes the growth of the succeeding community
b
climate change, because each community is determined by climate
c
extreme weather events, such as hurricanes, because they disrupt one community and open niches for a new community
d
tectonic events, such as earthquakes, because they disrupt one community and open niches for a new community

a

. ecological succession, because each community promotes the growth of the succeeding community

Explanation:

Ecological succession is the process in which species structure of an ecological community  changes over  time.

The given example shows ecological succession (secondary succession) as in the image series of community changes over hundred of years including growth of community from bare rocks to trees as each community is promoting growth of succeeding community. But the colonized community of trees after series of changes is disturbed by human activities or natural calamity (as shown in image) reduces an already established ecosystem is called secondary succession (Type of  ecological succession).

Hence, the correct option is a. ecological succession, because each community promotes the growth of the succeeding community

i think that it is plants