the illusion shows the forces in newton’s acting on three different blocks. Which boxes will move under these conditions?

yes? sounds right, but you didn’t ask a question.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.