The correct answer is C.
In fact the other options provided state the weaknesses that the Europeans encountered in their conflicts against the native Americans. They did not know the land, whose wilderness added extra dificulties for strangers, and in the case they needed reinforcements, the process of bringing them from Europe was long and costly.
But these weaknesses were rapidly outbalanced due to the huge superiority that the Europeans had in terms of weaponry if compared to the natives. They already knew gunpowder, while, natives Americans were still using bows and arrows. Moreover, the Europeans had properly organized armies, with its hierarchies, different units, experienced and skilled commanders, etc.
Correct answer choice is :
C) Primary source document
Explanation:
In the study of history as an educational rule, the main supply is an object, document, diary, manuscript, life, recording, or the other provide knowledge that was produced at the time below study. It is an inspired supply of knowledge regarding the subject. Although several primary sources stay in camera hands, others are put in information, libraries, museums, historical societies, and special collections. These may be public or non-public. Some are linked with universities and schools, whereas others are government organizations.
During the Cold War, the United States was focused on the foreign policy of containment. This idea focuses on stopping the spread of communism on an international scale. This policy explains why the US got involved in Cuba and Vietnam.
In Cuba, Fidel Castro and his followers overthrew Batista and established a communist government. Along with this, Castro established a good trading relationship with the Soviet Union. This resulted in the US attempting to overthrow Castro through the Bay of Pigs Invasion. However, this mission failed and only increased Castro's power and influence in Cuba.
As for Vietnam, the US was always interested in what was happening there, as they were afraid the communist system in North Vietnam would spread to the democratic country of South Vietnam. This act gave President Lyndon B. Johnson the power to take all necessary measures to protect US interests in Vietnam and to increase military action if needed.
I heard that there are two that remained. Angola and Mozambique.