Nicotine causes vasoconstriction in extremities

Steps:

• Recognize the effect as reduced blood flow due to narrowed vessels (vasoconstriction).
• Recall cigarette components: nicotine affects blood vessels, carbon monoxide impacts oxygen, carcinogens cause long-term damage, tar coats lungs.
• Match short-term vasoconstriction to nicotine's known action on arteries.
• Eliminate others as they lack direct vascular narrowing effects.

Why C is correct:

• Nicotine acts as a stimulant that constricts blood vessels, directly reducing supply to fingers and toes per its pharmacological definition as a vasoconstrictor.

Why the others are wrong:

• A. Carbon monoxide binds hemoglobin, lowering oxygen delivery but not causing vessel constriction.
• B. Carcinogens initiate cancer over time, unrelated to immediate blood flow changes.
• D. Tar builds up in lungs, leading to respiratory blockage, not short-term vascular effects.

Final answer: C