In which situations is work being done? a. hannah leans against her locker, but it doesn’t move. b. andy’s car rolls down a hill with the engine off. c. a wind turbine stands still on a sunny, windless day. d. a balloon expands as it is heated by the sun. e. james pedals a stationary exercise cycle that doesn’t move.

the oxygenated blood then leaves the lungs through pulmonary veins, which return it to the left heart, completing the pulmonary cycle. this blood then enters the left atrium, which pumps it through the mitral valve into the left ventricle. from the left ventricle, the blood passes through the aortic valve to the aorta.

deoxygenated blood leaves through the right ventricle through the pulmonary artery. from the right atrium, the blood is pumped through the tricuspid valve (or right atrioventricular valve), into the right ventricle.