Biology · Gaseous Exchange

The correct answer is Option C: Damage to alveoli reducing gaseous exchange. Smoking introduces toxins that damage the alveoli, which are the tiny air sacs in the lungs responsible for gas exchange. This damage leads to reduced functionality of the lungs, ultimately decreasing the efficiency of oxygen uptake and carbon dioxide removal.

Options A and D are incorrect because they incorrectly suggest that smoking has a positive effect on lung function and oxygenation, respectively. In reality, smoking is detrimental to both. Option B is also incorrect as it falsely claims that smoking reduces the risk of lung cancer, which is well-documented to increase cancer risk significantly.

This option is incorrect. Nicotine is a stimulant that can lead to temporary increases in heart rate but does not improve lung function. In fact, smoking generally harms lung function over time.

This option is incorrect. Smoking significantly increases the risk of lung cancer rather than reducing it. Tolerance does not apply in a beneficial context regarding cancer risk.

This option is correct. Smoking damages the alveoli, which are crucial for gas exchange in the lungs, leading to decreased oxygen intake and impaired respiratory function.

This option is incorrect. Smoking does not improve oxygenation; instead, it introduces harmful substances that impair the ability of hemoglobin to carry oxygen effectively.