2) What statement is true of muscle spindles? a) They sense tension in muscles; they inhibit the contracting muscles and excite the antagonist muscles.
b) They supply information on the length and rate of change in length.
c) They initiate movements of a sustained and repetitive nature.
d) They stimulate reflexive muscle relaxation.

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?