Answer:
B. the appearance of lichens and mosses in an area where a glacier has recently melted away
Step-by-step explanation:
Ecological succession, which refers to the series of changes that occurs over time in an ecosystem, can be of two types namely: primary succession and secondary succession.
Primary succession is a succession that involves an area where no form of life has grown previously, hence, the area of land is barren e.g bare rock. Primary succession is first colonized by species called PIONEER SPECIES e.g. lichens, mosses etc.
According to this question, "the appearance of lichens and mosses (pioneer species) in an area where a glacier has recently melted away" is an example of PRIMARY SUCCESSION.