Which of the following is a limitation of PPO plans? higher individual costs

limited to members of the U. S. military and their families

strict eligibility requirements

Investigator a has biological specimens that are coded and linked to identifiers of the source individuals. investigator a provides the specimens to investigator b but does not provide the individual identifiers. investigator b agrees not to re-identify the source individuals. is investigator b's research using the biospecimens human subjects research according to the definition of human subjects research in the federal regulations?