91Ó°ÊÓ

Respiratory proteins such as hemocyanin ___. a. contain metal ions b. occur only in vertebrates c. increase the efficiency of oxygen transport d. both a and \(c\)

The tracheal tubes of insects carry __ to tissues deep inside the body. a. hemolymph b. blood c. air d. water

In human lungs, gas exchange occurs at the ___. a. bronchi b. bronchioles c. alveoli d. pleural sacs

Which holds the most dissolved oxygen? a. warm, still water b. warm, running water c. cold, running water d. cold, still water

When you breathe quietly, inhalation is ___ and exhalation is ___. a. passive; passive b. active; active c. passive; active d. active; passive

During inhalation ___. a. the thoracic cavity expands b. the diaphragm relaxes c. atmospheric pressure declines d. both a and c

___ binds to hemoglobin even more strongly than oxygen does. a. Carbon dioxide b. Carbon monoxide c. Oxyhemoglobin d. Carbonic anhydrase

Most oxygen transported in human blood ___. a. is bound to hemoglobin b. combines with carbon to form carbon dioxide c. is in the form of bicarbonate d. is dissolved in the plasma

At high altitudes,____. a. nitrogen bubbles out of the blood b. hemoglobin has fewer oxygen-binding sites c. there are fewer \(\mathrm{O}_{2}\) molecules than at low altitudes d. both b and c

In fish gills, blood and water move ___. a. in the same direction b. in opposite directions c. through tracheal tubes d. in hemolymph