Which of the following is not a fitness benefit of hiking? a. upper body workout. b. vitamin d from the sun. c. cardiovascular workout. d. leg muscle workout.

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?