Can someone please give me a brief description of Plessy v. Ferguson?

Plessy v. Ferguson was a landmark 1896 U.S. Supreme Court decision that upheld the constitutionality of racial segregation under the “separate but equal” doctrine. The case stemmed from an 1892 incident in which African American train passenger Homer Plessy refused to sit in a car for Black people.

Explanation:

lincoln won 212 electoral votes to mcclellan's 21 votes, and lincoln beat mcclellan. is the main reason lincoln won in 1864.

the graph shows the spread of railways in the 1800s.

based on the graph, the conclusion that can be drawn about germany is answer d)   by 1880, germany had more rail lines than great britain and russia.