____ forms provide options for care which can be chosen by the patient for possible future care, and are not limited to situations when a patient is unresponsive.

Neurotransmitters are:

a. Chemicals released at synapses b. Ions that transmit information c. Proteins that diffuse across cell membranes

In sinus rhythms, P waves are found ________ the QRS complexes

Fill in the blank(s) with correct word