The path of blood through the heart begins with the right atrium receiving blood, which has circulated through most of the body. This blood is also relatively high in carbon dioxide, which is a product of metabolism in the tissues.
The circulatory system is made up of blood vessels that carry blood away from and towards the heart. Arteries carry blood away from the heart and veins carry blood back to the heart. The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide
<h3>Answer:<u><em> The Endosymbiotic theory</em></u></h3>
Explanation:
The Endosymbiotic Theory states that the mitochondria and chloroplast in eukaryotic cells were once aerobic bacteria (prokaryote) that were ingested by a large anaerobic bacteria (prokaryote). This theory explains the origin of eukaryotic cells.
