I believe it’s carbon dioxide, because you use your respiratory system to breathe in oxygen, and oxygen goes through your circulatory system. And you breathe out CO2.
Please find attached the labelled diagram
Explanation:
Please find attached the labelled diagram showing the parts
- Aorta - main and largest artery which branches into smaller arteries
- Artery - carry blood from heart to all other parts of the body
- Arterioles - carry blood and oxygen into smallest blood vessels
- Cells - single layer of endothelial cells in the walls of the capillary
- Capillaries - Carry oxygen to cells of tissues and organs
- Venules - carry blood flows from capillary into small venules
- Inferior Vena Cava - carry blood from legs and abdominal cavity to the bottom of right atrium
- Veins - blood vessels that carry blood to the heart
- Superior Vena Cava - carry blood from the brain and arms into the top of right atrium