Why do we use an object's mass, rather than its weight, to indicate the amount of matter it contains?​

During the first month of development, how many layers of cells make up the embryo? a. 1 b. 2 c. 3 d. 4

The frequency in wich you perform certain exercise depends on the blank of the exercise

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?