Question

which change in the evolutionary history of horses is documented by the fossil record?
a direct evolutionary path to modern - day horses
a gradual decrease in the number of toes
a gradual increase in the number of toes
transition from an aquatic habitat to land
a gradual decrease in body size

Explanation:

The fossil record shows that early horse ancestors had multiple toes. Over time, through evolution, there was a gradual reduction in the number of toes. For example, the earliest horse - like animals (e.g., Hyracotherium) had four toes on the front feet and three toes on the hind feet. As evolution progressed, the side toes became smaller and less functional, and modern - day horses have only one toe (the hoof).
The evolutionary history of horses is not a simple direct path (there were many branching and extinction events). Horses did not transition from an aquatic habitat (they have always been terrestrial or semi - terrestrial in their evolutionary history). And the body size of horses generally increased over time (from small, dog - sized early ancestors to larger modern horses).

Answer:

a gradual decrease in the number of toes