What Law was passed to protect the voting rights of all US Citizens including Blacks?

How did the completion of the transcontinental railroad change the lives of american citizens? a-it increased the wealth of all americans and enabled them to travel more.b-it made cross-country travel too expensive for ordinary americans.c-it decreased the safety of americans who moved to settle the plains.d-it shortened travel time between the east and west for all americans.

What is the waterway that links the atlantic and pacific ocean

1. what potential advantages could companies like standard oil offer consumers?