The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labelled 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.
-Which of the five species, labelled V-Z, is the common ancestor of the fewest number of species?
A) V
B) W
C) Y
D) Z

Question

The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labelled 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. 
-Which of the five species, labelled V-Z, is the common ancestor of the fewest number of species?
A) V 
B) W 
C) Y 
D) Z

Quizplus · Accepted Answer

V is the common ancestor of only one species, W.

The Horizontal Axis of the Cladogram Depicted Below Is a Timeline