5cfr 46 requires federal departments and agencies to rely solely on irbs to evaluate risks to subjects, protection against these risks, potential benefits of the research and the importance of the knowledge to be gained. true

That statement is False.
The Federal agencies actually have the independence to  to evaluate risks to subjects, protection against these risks, and potential benefits of the research on their own. IRB could give consultation to these agencies in the term of ethical behaviors, but they couldn't llimit the agencies' independence in operational decision.