Why are lichens a good pioneer species after a volcanic eruption? a. they are able to grow on moist soil. b. they are able to grow on bare rock. c. they are able to attract animals. d. they are able to grow without water.

The correct option is B.
Pioneer species refer to those species that are always the first to inhabit a destroyed ecosystem. These organisms are usually small, simple and able to produce their own food. Examples of pioneer species are lichens, bacteria, algae, fungi, etc. Lichens are able to serve as pioneer specie because they are capable of growing on bare rocks, they do not need soil to grow and survive.   

The question is asking to choose among the following choices that states the reason why are lichens a good pioneer species after a volcanic eruption, and base on my research, I would say that the answer would be letter B. They are able to grow on bare rock. I hope this would help 

The light is great source of energy