The first heart sound is the closing of the:
a. pulmonary semilunar and aortic semilunar valves
b. tricuspid and mitral valves
c. mitral and bicuspid valves
d. tricuspid and pulmonary semilunar valves
b. tricuspid and mitral valves
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During platelet plug formation, platelets begin to stick to
A. collagen with the assistance of von Willebrand factor. B. collagen with the assistance of prothrombin. C. prostacyclin with the assistance of activated factor V. D. prostacyclin with the assistance of thromboxane A2. E. proconvertin with the assistance of factor IX.
In __________ processes, the cell provides energy in the form of ATP to power the transport process.
a. active b. passive
Select all that contribute to the cerebral arterial circle.A) Internal carotid arteriesB) External carotid arteriesC) Anterior cerebral arteriesD) Posterior communicating arteries
What will be an ideal response?
The gender of the individual is determined at
A. gastrulation. B. fertilization. C. the third month. D. birth.