There are two types of succession that lead to the increasment of the ecosystem:
1. Primary succession is the change in the structure of an ecosystem represented with the increase of the ecological community on an area that has not been previously occupied by an ecological community such as area after the lava flow or glacial lake. The first organisms of primary succession are pioneer plants usually, lichens and mosses.
2. Secondary succession includes the step of removal of pre-existing community and after that, colonization of the new one.
B. It was an explanation for how the earth originated.
A gamma ray consist of gamma radiation.