Which principle is based on the concept that “if you don’t use it, you lose it”?

How harmful is it to smoke a pack of cigarettes a week?

Define physical activity. question 3 options: bodily movement produced by the contraction of muscles planned and structured exercise the ability to perform rigorous activity all the above

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?