A volcanic eruption that covers a region with lava and destroys the biodiversity of the ecosystem can have the following two consequences:
A. A very long period of time will pass before a new ecosystem can be established: The volcanic eruption can completely destroy the existing ecosystem, leaving a barren landscape. The lava may take a very long time to cool and solidify, and the process of weathering and soil formation that is necessary for new plants to grow can be slow. Therefore, it may take many years or even centuries for a new ecosystem to establish itself.
D. The ecosystem must now undergo primary succession: Primary succession is the process of colonization and establishment of plants and animals in an area that was previously barren, such as the area covered by lava in the case of a volcanic eruption. Since the existing ecosystem has been completely destroyed, the area will need to undergo primary succession for new plants and animals to establish themselves. This process can be slow and may take many years or decades, depending on the conditions of the environment and the availability of resources.