In Environment A, trees are growing back and some of the larger animals are returning to a logged forest. In Environment B, lichens and moss are growing on a rocky mountainside that was scraped bare as a glacier retreated. Now, hundreds of years later, some small grasses, shrubs, and animals live there.

Which statement best describes both situations?

Environment A is undergoing succession, and Environment B is not.
Environment A is not undergoing succession, and Environment B is.
Both environments are undergoing the same kind of succession.
Both environments are undergoing succession, but different kinds.