Describe the flow of blood through the human body, including through each of the four chambers of the heart. explain how the blood changes as it moves through various locations in the body.

Unoxygenated blood from veins enters the right atrium then it goes down to the right ventricle then out through the pulmonary artery to the lungs where it becomes oxygenated blood which then enters the heart through the pulmonary veins and it goes to the left atrium and then is pumped down to the left ventricle and out through the aorta to the arteries where it travels to different organs and becomes deoxygenated and then the cycle repeats itself.

Genetic engineering is the answer.