Which statement about the Supreme Court justices is true?

The statement that both B and C are true reflects the accurate process by which Supreme Court justices serve and are appointed. Justices of the Supreme Court serve for life unless they are impeached. This lifetime appointment allows justices to make decisions without the direct influence of the political pressures that come with elections. As such, they can maintain judicial independence.

Additionally, Supreme Court justices are appointed by the President of the United States, but these appointments require approval from the Senate, which is part of Congress. This process involves nomination by the President, followed by hearings and a vote in the Senate, ensuring a system of checks and balances within the government.

The other options suggest that justices are elected by the people or that they serve under different conditions, which does not accurately represent the established procedures and terms. Therefore, the combination of serving for life and needing presidential appointment with congressional approval makes the combination of statements B and C correct, leading to the selection of the option that includes both of these true elements.