Ineed . how did vietnam become a single communist nation?
question 2 options:

it did not become a single communist nations, but instead remained two separate countries until uniting and becoming a democracy in 2000.

u. s. troops withdrew and north vietnamese troops successfully invaded south vietnam.

north vietnam developed a strong economy that led south vietnam to request unification.

china negotiated a settlement between north and south vietnam that joined the two countries into a single communist nation

Correct

Explanation:

US President Richard Nixon had instituted a policy of "Vietnamization" in regard to the Vietnam War, which  emphasized that the United States needed to empower South Vietnamese forces to assume more combat duties.  He proposed drawing down US involvement in the war and seeking "peace with honor," as he put it.  By the time that President Nixon and US policy shifted to this sort of approach, it was too late to stave off the victory of the North Vietnamese and Viet Cong forces.  The US eventually withdrew its forces from Vietnam in 1973.  By 1975, Saigon, the capital of South Vietnam, fell to the North Vietnamese communist forces.  South Vietnam unconditionally surrendered to North Vietnam on April 30, 1975.

regarding the law, the 15th amendment was specifically designed thinking in the rights of black free men.

even though ratified on february 3, 1870, the promise of the 15th amendment would not be fully applied for a long time.poll taxes and literacy tests would allow southern states disenfranchise african americans. only in 1965 the voting rights for african americans would be actually able to vote in the south.

in 1965, president johnson signed the voting rights act, which aimed to overcome legal barriers that prevented african americans from voting as it was guaranteed by the 15th amendment to the u.s. constitution.

a drastic rise in oil prices ended decades of postwar.