If a molecule of CO2 released into the blood in your left toe is exhaled from your nose, it must pass through all of the following excepta. the pulmonary vein.b. the trachea.c. the right atrium.d. the right ventricle.

Which of the following body systems facilitates (but doesn't regulate) the functions of the other systems?respiratory systemendocrine systemdigestive systemcirculatory system

Which of the following is the main difference between your cardiovascular system and that of a fish? a. Your heart has two chambers; a fish heart has four. b. Your circulation has two circuits; fish circulation has one. c. Your heart chambers are called atria and ventricles. d. Yours is a closed system; the fish's is an open system.

Describe the disadvantages of an open circulatory system relative to a closed circulatory system.

One feature that amphibians and humans have in common isa. the number of heart chambers.b. a complete separation of circuits for circulation.c. the number of circuits for circulation.d. a low blood pressure in the systemic circuit.

In which of the following organisms does oxygen diffuse directly across a respiratory surface to cells, without being carried by the blood?a. a grasshopperb. a whalec. an earthwormd. a mous

What is the function of the cilia in the trachea and bronchi?a. to sweep air into and out of the lungsb. to increase the surface area for gas exchangec. to dislodge food that may have slipped past the epiglottisd. to sweep mucus with trapped particles up and out of the respiratory tract

What do the alveoli of mammalian lungs, the gill filaments of fish, and the tracheal tubes of insects have in common?a. use of a circulatory system to transport gasesb. respiratory surfaces that are infoldings of the body wallc. countercurrent exchanged. a large, moist surface area for gas exchange

The diaphragm is a large sheet of muscle that helps move air in and out of your lungs. Breathing is automatically controlled by the brain, but you can choose to hold your breath or breathe deeper. What kind of muscle do you suppose makes up the diaphragm? (Explain your answer.)