The relationship between the skulls of the extinct aquatic animal and the present-day gray whale best supports Darwin’s theory of evolution by showing that populations change slowly over time.
This is because the presence of similar anatomical features indicates that both species share a common ancestor, highlighting the gradual changes that occur in a lineage over time due to evolutionary processes. This aspect aligns with the idea that evolution is a slow and continuous process, producing diversity among living organisms while maintaining connections through common ancestry.