Mammals are more closely related to birds because they share a more recent common ancestor.
Explanation:
A tree diagram that represents hypothesised phylogenetic relationship illustrating evolutionary relationships among various entities (most often taxonomic groups) that are known to share a common ancestor.
An ancestors is one from whom a person is descended, whether on the father's or mother's side, at any distance of time; a progenitor; a forefather.
B. Mammals are more closely related to birds because they share a more recent common ancestor
