Question

the diagram is a cladogram that shows evolutionary relationships among several vertebrate groups. groups of reptiles are shaded. does the shaded region of the diagram represent a clade? a. yes, because it includes all the reptiles and their common ancestor. b. yes, because any set of connected lines in a cladogram may describe a valid clade. c. no, because birds evolved from the common reptile ancestor, but birds are excluded from the shaded region. d. no, because all vertebrates evolved from a common ancestor, and many vertebrates are excluded from the shaded region.

Explanation:

A clade is a monophyletic group that includes a common ancestor and all its direct descendants. The shaded region includes traditional reptiles but excludes birds, which share the same common ancestor as the other reptile groups shown. Since birds are descendants of this common ancestor but are left out, the shaded region is not a valid clade.

Answer:

C. No, because birds evolved from the common reptile ancestor, but birds are excluded from the shaded region.