Answer:
1st question: The public began to question the purpose of the war, the government's handling of it, and the morality of sending American soldiers to fight in a foreign land.
2nd question: I'm not quite sure, but it might be 1968 like you've listed there.
3rd question: In 1969, only 35% of the people believed that the US made a good decision to send troops to Vietnam, whereas 60% felt it was good in 1965
Step-by-step explanation:
Explanation for 1st question: By 1971, a majority of Americans believed that the war was a mistake, and they wanted the U.S. to withdraw its troops from Vietnam.
Explanation for 3rd question: A Gallup poll conducted in March 1969 found that 49% of Americans thought it was a mistake to send troops to Vietnam, where only 35% believed it was not a mistake.
hope this helps in any way! :)