Which of the following would increase the release of oxygen from red blood cells?

Mountain climbers often spend weeks adjusting to the lower partial pressure of oxygen at high altitudes before and during their ascent of high peaks. During that time, their bodies begin to produce more red blood cells. Some runners and cyclists prepare for competition by training at high altitudes or by sleeping in a tent in which PO2 is kept artificially low. Explain why this training strategy may improve an athlete's performance.

One of the many mutant opponents that the movie monster Godzilla contends with is Mothra, a giant mothlike creature with a wingspan of 7–8 m. Science fiction creatures like these can be critiqued on the grounds of biomechanical and physiological principles. Focusing on the principles of gas exchange that you learned about in this chapter, what problems would Mothra face? Why do you think truly giant insects are improbable?

SCIENTIFIC THINKING E-cigarettes pose a dilemma for public health officials. Because e-cigarettes produce fewer toxic chemicals than regular cigarettes, they may be a safer alternative for people who want to quit smoking but still crave nicotine. On the other hand, e-cigarettes may encourage nicotine addiction among teenagers. Evaluate the scientific evidence. Are e-cigarettes an effective aid for quitting cigarettes? What evidence supports the assertion that e-cigarettes are especially harmful to adolescents?

How does myoglobin aid diving mammals such as the Weddell seal?

When you hold your breath, which of the following blood gas changes leads initially to the urge to breathe again?

What causes CO₂ in the blood to decrease?

When you exhale, __________.

In the alveoli and lung capillaries, carbon dioxide and oxygen are exchanged by means of __________.