How did the mexican war lead to the civil war?

It did not lead to the Civil War, what led to the civil war was the war of 1812. That was when U.S.A recognized that it needed to become stronger, and slaves were transported to the United States and put in the working class under bad conditions. Child labor and prejudice began there as well.

the war was the westward expansion of the United States. All through the 19th century Americans believed it was their right to expand westward. At the time they believed they could conquer the people already living on the land and take it for the United States.

Explanation:

c or d both can be the answer

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.