Which of the protein test tubes showed digestion that was most like that of a real human stomach, and why? The test tube with pepsin, because that is the enzyme our body uses.

The test tube with only hydrochloric acid because that is the same as stomach acid.

The test tube with pepsin and hydrochloric acid because the pepsin enzyme is activated at the same pH as the stomach.

The test tube with pepsin and baking soda, because the pepsin enzyme is activated at the same pH as the small intestines.

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.