A cigarette is a small cylinder of finely cut tobacco leaves rolled in thin paper for smoking. The cigarette is ignited at one end causing the cigarette to smoulder and allowing smoke to be inhaled from the other end, which is held in or to the mouth; in some cases, a cigarette holder may be used, as well.
The breathing rate, or the number of times that a person breathes in and out in 1 minute, is often checked by health care professionals to determine the health of a person. The normal breathing rate is between 12 and 18 breaths per minute.
A typical rate of breathing (at rest) is about 12-20 breaths per minute. The rates at which oxygen, carbon dioxide, and water are exchanged with the body are very important. (We will later see how these rates are related to both energy production and cooling).