1) what evidence is there that the human species has been successful so far? explain.
2) what environmental pressures in the past do you think were most important in shaping the human species as it exists today?
3) what environmental pressures exist now that you think may be shaping the human species?
4) what environmental pressures do you think may affect humans as earth becomes more populated with humans in the future? explain how these pressures may affect human traits.

1) What evidence is there that the human species has been successful so far? Explain. 

Successful evolutionarily means "surviving and spreading geographically". Since we are far from extinction and we've spread all over the world, we are successful as a species. 

I believe that the environmental pressures that exist now and that may be shaping the human species are the use of land, the extraction of resources, greenhouse emissions and water use. This are being used by use more and more as we start overpopulating the earth.

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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.