Final answer:
The 1968 Tet Offensive demonstrated the strength and determination of North Vietnamese forces and led many Americans to question the U.S. presence in Vietnam.
Step-by-step explanation:
The 1968 Tet Offensive was significant because it demonstrated the strength and determination of North Vietnamese forces. The Tet Offensive was a surprise attack launched by the Vietcong and North Vietnamese forces on January 30, 1968, during the Vietnamese New Year called Tet. Despite not achieving a military victory, the massive scale of the attacks challenged the U.S. military's claims of success and led many Americans to question the U.S. presence in Vietnam.