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Blood flow that is directed through the lungs and back to

the heart is called ________.

a. unidirectional circulation

b. gill circulation

c. pulmonary circulation

d. pulmocutaneous circulation

Platelet plug formation occurs at which point?

a. when large megakaryocytes break up into thousands of smaller fragments b. when platelets are dispersed through the bloodstream

c. when platelets are attracted to a site of blood vessel damage

d. none of the above

In humans, the plasma comprises what percentage of the blood?

a. 45 percent

b. 55 percent

c. 25 percent

d. 90 percent