Question

One of the finest available sequences of fossils shows how horses have changed slowly and by subtle steps from small, shrub-browsing ancestors to the large, grass-grazing modern horse. a large number of fossil species have been named, and it is often difficult to decide on the identity of a fossil horse because transitional forms are common. this record of evolution best fits the idea of

Answer 1

This would be the gradualism model. This model shows that there are a number of transitional species for a given organism and that the changes to the family of species were very minor and took a long period of time. The changes are typically uniform across the species and lead to one species becoming another over this long time-frame.