Which is the correct direction of blood flow?
a. left ventricle --> pulmonary artery --> aorta
b. left ventricle --> left atrium --> aorta
c. right atrium --> right ventricle --> pulmonary artery
d. right atrium --> left atrium --> pulmonary artery

Option C, right atrium --> right ventricle --> pulmonary artery

Explanation:

The flow of blood on the right side includes the following

a)The  inferior and superior vena cava carrying the oxygen deficient blood, empties the blood into the Right Atrium

b)From the right atrium, the blood flows into the right ventricle and the tricuspid valve prevents the back flow of blood into atria.  

c)The blood then drains into the pulmonary artery through the  pulmonic valve

Hence,  the correct order of blood flow is option C

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