Which of the following is not a strategy for improving the long-term 6 of cities?
a. restoring natural ecosystems
b. reducing pollution and waste
c. increasing automobile use
d. compact and efficient land use

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?