How are primary and secondary succession similar?

Answer;
The primary succession is similar to secondary succession in that both types of successions involves the growth of a new environment.

Explanation;
Primary succession is a type of succession that occurs in lifeless areas; regions where the soil is incapable of sustaining life as a result of factors such as lava flows and sand dunes among others. Secondary succession occurs as a result of a major disturbance such as forest fire or a flood. They are similar in that both involve the growth of new organisms in an environment. However they differ in that primary succession occurs in a place where no life had been before, while secondary succession occurs in place where life had been before, but was destroyed. 

The answer your looking for is a food chain grid. it describes how nature can support itself and survival of the fittest comes into play..