The correct answers are: The United States sent more and more troops to Vietnam in the 1960s, The United States took over the defense of South Vietnam and The Gulf of Tonkin Resolution gave the president more authority to get involved in Vietnam.
During the early 1960s South Vietnam was at risk of infiltration and invasion by communists hence the US government and aimed to stop Soviet influence over South Vietnam. The South Vietnamese military had grown and developed considerably but was still incapable of defending the new nation thus the US sent more troops to Vietnam.
The attacks in the Gulf of Tonkin spur Congress passed the Gulf of Tonkin Resolution which authorizes the president to take all necessary measures that included the use of armed force against any aggressor in the conflict.
The way the U.S. involvement in Vietnam changed overtime was:
In the 1960s, there was an incident in the Gulf of Tonkin and President Johnson used this as an excuse to send more American soldiers to Vietnam in the 1960s.
This allowed the United States to effectively take over the defense of South Vietnam to fight both the Viet Cong and North Vietnam who sponsored the Viet Cong.
In conclusion, options A, C, and E are correct.
Find out more about the Viet Cong at https://brainly.com/question/11155923.
