How are primary and secondary succession similar and how are they different?

Primary and secondary succession occur after both human and natural events that cause drastic change in the makeup of an area. Primary succession occurs in areas where there is no soil and secondary succession occurs in areas where there is soil.

Both human and natural activities that result in a substantial change in the composition of an area create primary and secondary succession. In locations where there is no soil, primary succession takes place, and in areas where there is soil, secondary succession takes place.

Explanation:

not sure if this what   you'r looking for would be percent composition