Concept:Primary succession is the gradual establishment of a community in a completely lifeless area with no pre-existing soil or organisms.
Explanation:Succession is the orderly, directional change in the species structure of an ecosystem over time.
When an area has never supported a community, the process of colonization that begins there is called primary succession.
Typical starting points include bare rocks after glacial retreat, cooled lava fields, and newly formed sand dunes.
These habitats lack soil, so the first living things must be tough pioneer species such as lichens and mosses.
As pioneer species grow and die, they break down rock and build up a thin layer of soil, which allows grasses, shrubs, and eventually trees to take root.
In contrast, secondary succession occurs after a disturbance clears an existing community but leaves the soil and some seeds or roots behind.
Because the question states that there is no pre-existing community, the process described must be primary succession.
Answer:B. primary succession