Final answer:
Primary succession occurs when new land is formed, and pioneer species like lichens and mosses help break down the rock and create soil.
Step-by-step explanation:
Primary succession occurs when new land is formed, such as after a volcanic eruption. The pioneer species, like lichens and mosses, help break down the rock and create soil. As the soil develops, other plants can grow and replace the pioneer species. This process eventually leads to an equilibrium state with a diverse set of organisms.