Superior/inferior vena cava - right atrium - right ventricle - pulmonary artery - lungs(for oxygenation) - pulmonary vein
O M G i just did that one on Plato
well anyway i think the answer was the the skin because any thing that invades the body is a threat to the immune system.
Answer:
an disease caused by the lack of some essential or important element in the diet, usually a particular vitamin or mineral.
Answer:
Prepares to fight or run from danger
Explanation:
