Final answer:
Option (A), A rapid respiratory rate is known as Tachypnea, a term indicating breathing faster than the usual rate and is a vital sign monitored for health condition changes.
Step-by-step explanation:
A rapid respiratory rate is known as Tachypnea. This term is used to describe the condition of breathing faster than the normal rate. The respiratory rate is an important indicator of health status and can change during illness or a disease condition.
It's controlled by the respiratory center in the medulla oblongata, which responds to changes in carbon dioxide, oxygen, and pH levels in the blood. Conditions like hyperpnea and hyperventilation also involve changes in breathing patterns but are differentiated by the oxygen needs of the cells or the levels of carbon dioxide in the blood.