An action potential begins in a myocardial cell when ________ enters the cell, giving it a ________ charge

Rats belong to the order of gnawing mammals called ____________________

Fill in the blank(s) with correct word

According to whom, a physician must register and pay a fee before he or she is granted permission to administer controlled substances?

a. Drug Enforcement Administration b. Federal laws c. State laws d. Controlled Substances Act