The sticky brown substance in tobacco smoke that carries most of the carcinogens is
Correct answer: D. tar
- A. nicotine
- B. carbon monoxide
- C. ash
- D. tar
Explanation
Tar condenses in the airways and contains the chemicals that mutate DNA and cause cancer, while nicotine addicts and carbon monoxide starves tissues of oxygen. Each component has its own signature harm.
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About Human Respiratory System
The human respiratory system conducts air to the alveoli, where oxygen and carbon dioxide exchange occurs across thin respiratory surfaces. Questions cover the nasal passage, trachea, bronchi, lungs, diaphragm and intercostal muscles, ventilation mechanics and gas transport, while distinguishing breathing and gaseous exchange from cellular respiration.
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