Question

multiple choice question
which tree specifies a common ancestor?
○ (b)
○ (a)

Explanation:

In phylogenetic trees, nodes represent common ancestors. Tree (b) has internal nodes that show shared common ancestors for groups (B & D, A & C, and an overall common ancestor for all four). Tree (a) only shows two separate unconnected groups with no shared common ancestor for all four taxa, nor does it structure subgroups with clear shared ancestors in the same way as (b).

Answer:

(b)