The following is an example of dynamic stretching: Question 4 options:

Holding the hurdler stretch

A partner pushing your back while you hold the hamstring stretch

Standing and pulling the arm across the chest

Doing lunges while walking

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?