Final answer:
Primary succession is true for occurring after events like volcanic eruptions, which create new land devoid of life. Pioneer species initially colonize this barren land, initiating an ecological succession leading to a mature ecosystem.
Step-by-step explanation:
The statement that primary succession can occur after a major event such as a volcanic eruption is true. Primary succession refers to the colonization of living organisms in an area where there was previously no life and no soil, such as the new land formed from a lava flow. In contrast, secondary succession occurs in previously colonized areas that have been disturbed but still have soil, for example after a fire or flood.
These initial colonizers are known as pioneer species, and they play a crucial role in transforming the barren land into soil that can support other life forms. Over time, more complex plant and animal communities develop, gradually replacing the pioneer species, and leading to a mature ecosystem.