Which of the following is among the most common causes of the common cold?

The leaf-shaped structure located superior to the larynx is called the:

A. epiglottis. B. vallecula. C. cricoid ring. D. thyroid cartilage

Catecholamines and noncatecholamines are:

A) adrenergic agonists B) adrenergic antagonists C) sympatholytics D) muscarinics