Question

What do we all these upper and lower layer of blood?

Answer 1

Answer:

Hello

Explanation:

Pulmonary circulation also includes capillary circulation. Oxygen you breathe in from the air passes through your lungs into your blood through the many capillaries in the lungs. Oxygen-rich blood moves through your pulmonary veins to the left side of your heart and out of the aorta to the rest of your body.

Answer 2

Answer:

Veins are blood vessels that carry blood towards the heart. Most veins carry ... carry blood away from the heart. Veins are less muscular than arteries and are often closer to the skin...............