Lack of oxygen to the brain

I don't exactly know what your asking but here ya go

Brain hypoxia is a medical emergency because the brain needs a constant supply of oxygen and nutrients to function properly. There are several causes of brain hypoxia. They include drowning, suffocating, cardiac arrest, and stroke. Mild symptoms include memory loss and problems with motor function, such as movement

antibodies

explanation:

answer(b) keep oxygenated and deoxygenated blood separate;