Primary succession is when, for example, a volcano explodes and there is nothing left and even the soil is ruined. It would take at least a hundred years for the land to be like it was before the volcano erupted. Secondary succession is when, for example, a wild fire happens but the soil is not ruined. It would take at least 25-50 years for the land to be like it was before the fire.
It looks correct to me. Good job
Moving faster will increase the kinetic energy
The difference between them is that an ecosystem is a community of organisms and their environment. And a biosphere is all the living organisms.