The culture of the plains indianas was changed by:

The correct answer is A. The introduction of the horses by the spanish.

Explanation:

The culture of the Plains Indians changed by the introduction of horses by the Spanish.

The Indians in the Americas did not have horses. These animals were brought by the Spanish conquerors. So when the Spanished conquered territories in the Americas, the use horses as they did in Spain. This really benefitted the Indians in many ways. The obvious one, transportation. Horse ride faster than any other known method by the Indians in the Plains. And they could carry more things that a human. Just let's remind that Aztec's servants used to run 500 kilometers from the city of Tenochtitlan(nowadays modern Mexico City) to the port of Veracruz, to bring Emperor Monctezuma fresh fish to eat.  

in 1803 the louisiana purchase took place, doubling the size of the country. by 1840 almost 7 million americans had migrated westward in hopes of securing land and being prosperous. the belief that settlers were destined to expand to the west is often referred to as manifest destiny.

explanation:

nations must cooperate to bring about and maintain world peace.

nations must not wage wars or commit war crimes in a desire to control other nations.

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