Question

if blood is in short supply, which blood type would be the most beneficial to have on hand if someone needed a blood transfusion?
o+
o-
ab+
ab-

Explanation:

Blood type O - is the universal donor. It has no A, B, or Rh antigens on its red blood cells. So, it can be transfused to people with various blood types (A, B, AB, O, positive or negative) without causing an immediate immune reaction in most cases. Other types like O + can't be given to Rh - negative recipients, AB + is a universal recipient (not donor), and AB - also has limitations compared to O -.

Answer:

O -