d- An ecosystems organisms become larger as succession progress.
Explanation: Ecological succession is the gradual replacement of one community by others. It occurs still the stable community or climax community is established. As the community is replaced, the organisms are also replaced by other communities. In the first or pioneer aquatic community the smaller phytoplanktons are replaced by larger herbs and shrubs of the new community. Then they are also replaced by woody trees of a stable community. sometimes natural disturbances cause the succession. It leads to a more stable succession.
