Describe a situation in which succession my occur.

The renewal of a forest after a fire: The fire itself destroys a majority of different types of trees and plant life. Because seeds and roots and other plant and tree parts remain in and on the soil, gradually the plants and trees begin to grow again and eventually returns to the state of the original ecosystem.The renewal of a crop after harvesting: A crop is completed harvested when it becomes ripe. Without new seeds being planted, the crop can regenerate the following year due to the plants and seeds that remained after harvesting. A forest renews after logging: A large amount of trees were chopped down by loggers in order to create building materials. Over time, trees grow in and the area returns to its previous state. 

They create genetic variations

Might need you in a few weeks c: