Answer: The integumentary system helps the immune system by The skin acts as a barrier to keep out pathogens (B)
Explanation:
<h3>The blood in the pulmonary artery is going to the heart to collect oxygen, and therefore has a low content of oxygen. So, the blood in the pulmonary artery is a violet colour because it has low oxygen. The blood in the pulmonary vein is oxygen rich, and so it gives a scarlet</h3>

Chemo is for cancer not benign