Final answer:
American horses exhibit traits and cultural significance developed after their reintroduction by Spanish explorers, not derived from Roman influence. The traits of the horses in the Americas evolved as they were adapted by Native American tribes for their new roles in these cultures.
Step-by-step explanation:
The traits of American horses, thanks to the Romans, are not directly influenced by Roman culture or practices. In fact, horses were reintroduced to the Americas by the Spanish during the period of conquest and colonization. The Romans did use animals, such as the dromedary camel, for patrolling the extreme conditions of their frontiers, but this had no impact on the traits of American horses.
Horses originally from the Americas, became extinct on the continent after migrating to Asia and were reintroduced later by Spaniards such as Hernán Cortés and Francisco Vásquez de Coronado. The introduction of horses revolutionized Native American cultures, particularly the Plains and Plateau Native Americans, transforming their ways of life from hunter-gathering and farming to more nomadic lifestyles following bison herds.
Therefore, the correct answer is C) There were no specific traits influenced by the Romans. American horses developed their traits and significance in American culture not through Roman influence, but through reintroduction and adaptation after European contact.