Not giving her seat up to a white man or a segregated bus. It sparked a lot of conflict which led to peaceful protest.
It was an example of preparedness
The best-known power of the Supreme Court is judicial review, or the ability of the Court to declare a Legislative or Executive act in violation of the Constitution, is not found within the text of the Constitution itself. The Court established this doctrine in the case of Marbury v. Madison (1803).
I can’t see the choices on my phone, but the “separate but equal” doctrine was reinforced in the Plessy Vs Ferguson court decision. It was reversed in 1954 with the Brown vs Board decision.