Answer:
This a process of ecological succession that occurs in every environment.
Explanation:
The first organism which starts growing on the rocky surface are the mosses and grasses. We called it primary succession because mosses and grasses are the first organisms which lives on rocky surface. After some time, these mosses disappear or removed due change occur in the environment and new species such as higher plants start growing on these surface. The mosses die and provide nutrients for the higher plants. We called it secondary succession because the mosses are removed and higher plants takes their place.