Answer:
Primary succession is the type of succession which occurs in areas where there was no form of life before or it occurs in areas where the previous form of life has fully been eradicated with not even the soil present from that ecosystem. For example, a land where lava eruption has occurred.
A secondary succession is the type of succession which occurs in areas where there was life before which was removed by natural disasters like fire, flood or by human activities. This kind of areas might have the soil texture and composition to support life again. But for primary succession, the rocks will eventually have to be broken down and soil particles would form with the passage of time. Then only the land will be able to support life. Hence, primary succession takes longer to occur.