What is a substance made of two or more elements that cannot be separated by physical means

The case of brown v. board of education was started when a. oliver brown's daughter had to walk 21 blocks to the nearest school when an all-white school was only 7 blocks away. b. oliver brown's son was caught at a sit-in at the local school district. c. oliver brown's son was unable to participate in the school's all-white football team. d. oliver brown's daughter was unable to attend high school because there were none for her to attend.

The diagram shows fossils buried in layers of rock. which conclusion is best supported by the diagram?

What were the four terms that american had to agree in order to live in mexico texas