Under NFPA classification, which of the following presents the least significant threat of producing ignitable vapors at ambient conditions?

Agonists are used to a. enhance the effects of another drug

b. treat symptoms without any other drug. c. give flavor to another drug. d. prolong the action of another drug.

When you turn your head, ____. 

A. all cervical vertebrae pivot on one another B. the 7th cervical vertebra pivots on the 1st thoracic vertebra C. the atlas pivots around the axis D. all cervical vertebrae move as one unit E. the cervical vertebrae are compressed against each other