Final answer:
The horse very likely originated in the Americas and became extinct there after prehistoric times. The Spanish brought horses to North America in the 16th century, and these horses were different from the horses of today.
Step-by-step explanation:
The horse very likely originated in the Americas but migrated to Asia over the Bering Strait land bridge and became extinct in the Americas after prehistoric times. The horse was completely unknown to the Native Americans prior to the Spanish conquest. The Spanish brought horses to North America in the 16th century, and these horses were different from the horses of today.