What questions should a historian ask to determine whether a source is credible? Select three options. Is it relevant to the subject or event? Is the writing style clear and professional? Does it contain information that is outdated? Is the author an expert on the subject or event? Does it explain a version of how the event occurred?

Will have the greatest effect on human health. pollution in the a. troposphere b. stratosphere mesosphere d. thermosphere

Who did the first work in creating vaccines

Match each idea to the correct principle of government. federalism separation of powers checks and balances divides the powers of government into different branches arrowright divides the powers of government between central and state governments arrowright each branch of government has certain powers that prevents the abuse of power on the people arrowright