Chapter 20 Discussion Questions
- People who appear to have drowned can often be revived, in some cases after being underwater for as long as half an hour. In every case of full recovery after extended submergence, however, the person has been submerged in very cold water. Try to explain this observation.
- Why can't humans or other mammals breathe water as well as air? In other words, what is it about the lung as a gas exchange organ that makes it unable to function effectively when filled with water?
- The evidence associating lung cancer with smoking is overwhelming, and as you have learned in this chapter, we now know in considerable detail the mechanism whereby smoking induces cancerŅit introduces powerful mutagens into the lungs, which cause mutations to occur; when a growth-regulating gene is mutated by chance, cancer results. The process is no more mysterious than the fact that death results from shooting shotguns at random in crowded football stadiums. In light of this, why do you suppose that cigarette smoking is still legal?