That is the Aorta. The main artery of the body.
Arteries
Veins carry oxygen depleted blood to the heart.
By definition, ALL arteries carry Oxygen rich blood. Veins carry oxygen depleted blood.
This is through the Pulmonary Circulation.
Capillaries carry Oxygenated (oxygen rich) blood and De-oxygenated (oxygen depleted) blood.
The Lungs
The pulmonary artery carries blood away from the heart and it is low in oxygen.
When you inhale, your breath is drawn into your lungs, and is exchanged for Carbon Dioxide. The oxygen is 'traded' for Carbon Dioxide from your blood vessels, which leaves the body when you exhale. In other words, inhaling brings Oxygen to your blood.
veins
because oxygen brings food to the cell
because oxygen brings food to the cell
Dark blood is blood from which the oxygen has been depleted. Once it is filled with oxygen again (in the lungs), it becomes lighter in color.
Blood brings food and oxygen to your cells.