Answer:
Primary succession: It is defined as the development of growth of a community in an area which was previously barren, unoccupied, and there was no vegetation occurs. Example of primary succession are: newly formed dessert, ponds, and bare rock.
Secondary succession: It is defined as the development of the community which was previously occupied in such area, and which has primary vegetation but due to some factors (external or internal) damaged or disturbed. Example of secondary succession are: while an area affected by natural factors, such as earthquake, flood, etc, and deforestation.