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

Anatomy & Physiology

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Select all that contribute to the cerebral arterial circle.A) Internal carotid arteriesB) External carotid arteriesC) Anterior cerebral arteriesD) Posterior communicating arteries

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Anatomy & Physiology

In __________ processes, the cell provides energy in the form of ATP to power the transport process.

a. active b. passive

Anatomy & Physiology

The gender of the individual is determined at

A. gastrulation. B. fertilization. C. the third month. D. birth.

Anatomy & Physiology

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.

Anatomy & Physiology