Question

why is it important for your heart to keep oxygen-rich blood separated from the oxygen-poor blood

Answer 1

The oxygen-poor blood in our body is sent to lungs for purification.

Here the lungs separate the carbon dioxide and purify the blood.

If both oxygen-poor and oxygen-rich blood get mixed then the process of purification will be stopped, resulting in the death of the person.

So it is important for the heart to keep them separate.