Question

what does the first point on an evolutionary tree show?
the homologous trait
the species size
the last species
the common ancestor

Explanation:

An evolutionary tree (phylogenetic tree) is used to represent the evolutionary relationships among species. The first point (root) of an evolutionary tree represents the common ancestor from which the other species or groups of organisms in the tree have evolved. Homologous traits are related to shared characteristics due to common ancestry but are not what the first point represents. Species size is not indicated by the first point of an evolutionary tree. The "last species" is incorrect as the first point is the starting point of evolution for the group, not the last species.

Answer:

the common ancestor