Answer:
To avoid mixing.
Explanation:
There are specific arteries and veins of the heart which carries blood by using systemic and pulmonary circulation in order to avoid mixing of oxygenated blood with deoxygenated blood. Oxygenated blood is rich in oxygen that is needed by our body that is transported by pulmonary circulation, while on the other hand, the deoxygenated blood carries by systemic circulation from the cells to the lungs due to waste material in it in the form of carbondioxide gas.
