The horizontal axis of the cladogram depicted is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. the labeled branch points on the tree (v–z) represent various common ancestors. let’s say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. in darwin's tree of life, each fork in the tree represents
a) groups of extinct organisms.
b) the most recent common ancestor of the subsequent branches.
c) morphologic gaps in the fossil record.
d) groups of living organisms.

The answer is B. The most recent common ancestor.

Explanation:

Cladograms are used to illustrate relationships related to morphological and evolutive traits. So then,  in a cladogram when organisms are closely related, they appear closer in the branches. Common branches and nodes mean close relationships and common ancestors on a scale of time.

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.