Question

Species A is the ancestor of species B.
Species B is the common ancestor of species C and D.
Species C and D are the descendants of species B.
Based on the information above, imagine two new species, E and F, descended from species C, and two new species, G and H, descended from species D. The most recent common ancestor of species E, F, G, and H is species _____.
A. a
B. b
C. c
D. d

Answer 1

The most recent common ancestor of species E, F, G, and H is species B.

Here’s a breakdown of the relationships:
- Species A is the ancestor of species B.
- Species B is the ancestor of species C and D.
- Species C gives rise to species E and F.
- Species D gives rise to species G and H.

Since both E and F descend from C, and G and H descend from D, the most recent common ancestor for all four (E, F, G, and H) is species B.

So the answer is **B. b**.