A medicine is a chemical substance that is used to treat, prevent or diagnose a disease.
Answer:
depends how old are you? boy or girl? lol
Explanation:
Dilation of the pupil occurs when the smooth cells of the radial muscle, controlled by the sympathetic nervous system (SNS), contract. Constriction of the pupil occurs when the circular muscle, controlled by the parasympathetic nervous system (PSNS), contracts.
Phase C. 3 of clinical testing is required by the FDA before drug approval and uses the greatest number of subjects. These clinical trials are randomized and controlled trials on large patient groups.