Which factor can cause secondary succession?
clear cutting
glacial melting
competition
predation

clear cutting

An ecological succession is progressive change in biological community living in an ecosystem with respect to change in non-living components in an ecosystem and time until the ecosystem attains stability. Secondary succession are the changes in the biological  community that occur after an ecosystem which was previously colonized but disturbed by natural or man-made disturbances for example forest fires, flood, clear cutting. Clear cutting of vegetation or forests will lead to secondary succession. As, seeds of previously existing plants will be present in the soil which will promote plant growth. The roots present in the soil of cut trees or other vegetation will promote regeneration of new plants. The soil will be fertile enough to sustain plant growth. Hence, secondary succession will ensure faster colonization of biological communities in an ecosystem.