In this task, you are given a paragraph, and your task is to construct a question from the given passage. Construct question in such a way that (i) it is well explained in the paragraph, (ii) the words may/may not be present in the paragraph, (iii) it should start with what/how/describe. Avoid creating a question that (i) is just relevant to one or two sentences, and (ii) not relevant to passage.
Q: Two large veins bring blood to the heart. The blood enters the right atrium. The blood flows through the tricuspid valve. The blood travels into the right ventricle. The blood goes through the pulmonary arteries to the lungs. Blood picks up oxygen in the lungs. Oxygenated blood enters the left atrium. Blood goes to the left ventricle. Blood leaves the heart via the aorta to the rest of the body. The deoxygenated blood returns to the heart.
A:
How does the heart work?