15. Primary succession in a forest generally follows which sequence? a. Forest fire; pioneer species; willows; shrubs

b. Abandoned farm; shrubby weeds; cottonwoods; pine trees

c. Flood; mosses; weeds; shrubs

d. Exposed rock; lichens; shrubs; trees

Option D

Explanation:

Primary succession usually occurs when newly exposed rock is colonized by living things for the first time and in this context, a newly exposed rock is first colonized by lichens (the pioneer species) then followed by shrubs and then tree.

kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above