Which statement regarding smoking is FALSE?

The statement that smoking increases the oxygen-carrying capacity of blood is incorrect. In fact, smoking has several adverse effects on the body's ability to transport oxygen effectively. When someone smokes, substances within cigarette smoke, like carbon monoxide, bind to hemoglobin in red blood cells far more strongly than oxygen does. This reduces the amount of oxygen that hemoglobin can carry, leading to decreased oxygen-carrying capacity.

In contrast, smoking also contributes to increased carbon monoxide levels in the blood, which further exacerbates this issue. The presence of carbon monoxide not only competes with oxygen for binding sites on hemoglobin but also promotes other physiological changes that can impair oxygen delivery to tissues.

Moreover, smoking does not promote vasodilation; rather, it can cause vasoconstriction and damage to blood vessels over time, which increases cardiovascular risks. Thus, the notion that smoking increases oxygen-carrying capacity contradicts the known physiological impacts of smoking on the body.