How is the degree of evolutionary relatedness between two organisms primarily determined using a phylogenetic tree?

By counting the number of physical similarities between the two organisms.

By identifying the most recent common ancestor the two organisms share.

By measuring the distance between their names at the top of the tree diagram.

By comparing the physical environments in which the two organisms currently live.

If biologists state that two species are very closely related, what does this imply about their common ancestor?

It was physically identical to both modern species.

It lived a relatively short time ago.

Their common ancestor is still alive today in an unchanged form.

They do not share an ancestor with any other species.

The bird and the bat, because they both can fly.

All three are equally related to one another.

Species X and Z are most closely related.

All three species are equally related.

Species Y is more closely related to Species X because their common ancestor is more recent.

Species Z is the ancestor of both Species X and Y.

It proves they are in the same evolutionary family.

It shows they evolved at the same time.

Nothing definitive; relatedness is found by tracing branches to a common ancestor.

It means they are more closely related than either is to a fish.