Final answer:
The fossil record shows evidence of toe number reduction, changes in tooth shape, and an increase in size in horse evolution. Early horses had multiple toes and simpler teeth, but as the environment changed, their anatomy adapted to new diets and predator avoidance. The correct answer is option A., B and D.
Step-by-step explanation:
The trends in the fossil record that are evident in the evolution of the horse include:
- A. toe number reduction - The earliest horses had four long toes, which over time evolved into a single large toe that became a hoof.
- B. change in tooth shape - As horses adapted to grazing on tough grasses, their molars became longer and covered with cement to grind food effectively without wearing out.
- D. increase in size - From the size of a fox to that of the modern horse, the fossils show that horses became taller, which likely helped them to see predators in tall grasses.
Evidence such as the shape of leg bones and teeth show how horses evolved to adapt to changing environments and niches, particularly in response to a drying climate and the replacement of forested landscapes with grasslands.