C. Learning to domesticate plants and animals changed the way
humans lived.
Answer:
Letters and publications written by Nazi leaders before the Second World War.
Explanation:
This answer is correct because this historian is searching for the motives of these perpetrators, letters and publications can tell their thoughts and conversations.
Causes of US failure in Vietnam include b) The United States supported corrupt leaders in Vietnam and d) Only a few US soldiers fought with honor.
One of the biggest issues of the Vietnamese war was that the United States went in because of anti-communism above all other reasons because of the Truman Doctrine. The South Vietnamese leaders were not well liked and were overall corrupt. The knowledge of this back home created a lot of public tension and actually caused soldiers to feel they weren't fighting for a good cause, or even commit war crimes as seen in the My Lai Massacre.
Hope I could help!
