Imagine what happens in an empty lot that has been cleared of all living things. As in a garden that is no longer planted, only soil remains. Weeds begin to grow in the soil. At first, only plants that need full sun to sprout grow there. But over time, these plants grow taller and shade the ground. Then, a different kind of plant begins to grow there, one that grows only in shady areas. Eventually, the lot is covered in mostly plants that sprout in shade. Please help