Which of the following statements about biogeochemical cycles is not true?
a. biogeochemical cycles include living and nonliving elements.
b. the rock cycle is a biogeochemical cycle.
c. biogeochemical cycles are an important part of the earth system.
d. carbon, nitrogen, and oxygen cycles are biogeochemical cycles.

≅200-130 milions years ago pangea splited in 2 continents

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.