The answer is burning coal! Please forgive me if I get this answer wrong!
Planet earth was probaly formed 30,thousand years ago the first life probably evolved 29 thousand years ago
Answer: Capillaries connect the arterial system — which includes the blood vessels that carry blood away from your heart — to your venous system. Your venous system includes the blood vessels that carry blood back to your heart. The exchange of oxygen, nutrients, and waste between your blood and tissues also happens in your capillaries.
