Answer:
1. Sentence 1
Step-by-step explanation:
According to the given excerpt, the author describes how the US Supreme Court does not reflect the US population as it has been slow in fully integrating people of diverse races into the system and up till now has no Asian or Hispanic has been appointed as member of the court.
The main idea in the excerpt is sentence 1 because it gives the main idea that the US Supreme Court does not reflect the population, while the other sentences are supporting details.