Nicotine's Cardiovascular Impact

Steps:

• Identify nicotine as a stimulant that affects the nervous system and blood vessels.
• Link nicotine to adrenaline release, causing vasoconstriction and elevated heart rate.
• Distinguish nicotine's direct effects from other smoke components like tar or carcinogens.
• Match the primary risk to the option describing hypertension.

Why C is correct:

• Nicotine activates the sympathetic nervous system, releasing catecholamines that constrict arteries and raise blood pressure, per physiological definitions of stimulant effects.

Why the others are wrong:

• A: Bronchitis and emphysema result from irritants and tar in smoke, not nicotine's stimulant action.
• B: Airway cancer stems from polycyclic aromatic hydrocarbons and other carcinogens, unrelated to nicotine.
• D: Reduced birth weight links to carbon monoxide reducing fetal oxygen, with nicotine playing a minor role.

Final answer: C