Why did the issue of voting lead to another constitutional amendment in the late 1800s?
congress decided to extend voting rights to white women.
african americans had achieved equality in most other areas.
poor white southerners were blocked from voting by poll taxes.
congress was worried that white southerners would stop african americans from voting.

The correct answer is the last one: Congress was worried that the white Southerners would stop African American from voting.

The 14th amendment (1868) granted former slaves US citizenship. It also stated that they wouldn't deprive any person from freedom, life or property without the due process of law, they wouldn't violate any citizen's privilege or inmunity and should guarantee to every citizen equal protection of the laws. The 15th amendment (1870) granted African American the right to vote, prohibiting the use of race or color as a reason to deny someone their legal right to vote.

d Congress was worried that white Southerners would stop African Americans from voting.

the committees of correspondence were the american colonies’ means for maintaining communication lines in the years before the revolutionary war. in 1764, boston formed the earliest committee of correspondence to encourage opposition to britain’s stiffening of customs enforcement and prohibition of american paper money. the following year, new york formed a similar committee to keep the other colonies notified of its actions in resisting the stamp act. in 1773, the virginia house of burgesses proposed that each colonial legislature appoint a committee for intercolonial correspondence. the exchanges that followed built solidarity during the turbulent times and bring about the formation of the first continental congress in 1774.

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.