Toxic chemicals that can damage human health come from both natural resources and human activities.
a. true
b. false

If a doctor needs using a medical imaging machine, a might be called to assist the doctor.

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?

The centers for*blank* control and prevention safeguards americans from health, safety, and security hazards and threats.