Which letter represents the part of the earth's interior in this diagram that contains the oldest rocks on earth?

sadness is not good

explanation:

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.

i think that is new experiments yield untrustworthy data and should be carefully considered, because you don't know what will happen with the experiments.

if you add everything up correctly you should get 69 i got this because 50 plus 19 is it