Which correctly lists the weeks associated with each trimester? first trimester (weeks 1–12); second trimester (weeks 13–26); third trimester (weeks 27–40) first trimester (weeks 27–40); second trimester (weeks 13–26); third trimester (weeks 1–12) first trimester (weeks 1–3); second trimester (weeks 4–6); third trimester (weeks 7-9) first trimester (weeks 7–9); second trimester (weeks 4–6); third trimester (weeks 1–3)

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?