Answer:
The Primary succession can be defined as an area that was previously unoccupied, barren, and uninhabited and there was no vegetation.
The secondary succession can be defined as the area in which previously there is a growth of a community and it is occupied, inhabited and has primary vegetation but it was got disturbed due to some external or internal factors.
Example of primary succession: Bare rock, Desert, while that of secondary succession will include earthquake, flood, forest fire etc.