What is a Promise Ring. A promise ring, sometimes known as a pre-engagement ring, is a simple piece of jewelry that is given as a symbol of a committed, monogamous relationship. In some cases, the promise ring symbolizes purity and a decision to remain celibate until marriage.
Noun. 1. external respiration-the bodily process of inhalation and exhalation; the process of taking in oxygen from inhaled air and releasing carbon dioxide by exhalation. breathing, respiration, ventilation. artificial respiration-an emergency procedure whereby breathing is maintained artificially.
Respiration include four processes: 1  Pulmonary ventilation (air in/out, gas exchanged in lungs) 2  External respiration (gas exchanged between blood and alveoli in lungs) 3  Transport of respiratory gases (transport of oxygen and carbon dioxide)  Internal respiration (gas exchange between blood and tissues)