When you hold your breath, which of the following first leads to the urge to breathe?a. falling CO2b. falling O2c. falling pH of the bloodd. rising pH of the blood

Which respiratory organ is most often found only in fully aquatic animals?

Gas exchange in the gills of a bony fish is maximized by which of the following?

For a body surface to be a respiratory surface, it must __________.

Complete the following concept map to review some of the concepts of gas exchange. a. b. c. d. e. f. g.

Which of the following promotes oxygen release from hemoglobin?a. a decrease in temperatureb. an increase in O2 levelc. a decrease in pHd. a decrease in carbonic anhydrase activity

When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?a. rising O2b. falling O2c. rising CO2c, falling CO2

Countercurrent gas exchange in the gills of a fisha. maintains a gradient that enhances diffusion.b. enables the fish to obtain oxygen without swimming.c. means that blood and water flow at different rates.d. allows O2 to diffuse against its partial pressure gradient

When you inhale, the diaphragma. relaxes and moves upward.b. relaxes and moves downward.c. contracts and moves upward.d. contracts and moves downward.