Which of the following blood types is known as the universal donor?
a. A b. AB c. B d. O e. Rh


Sagot :

Blood type O (letter D) is known as the universal donor.
The types of blood is also classified by "rhesus/ Rh". It refers to your blood if it has antigen or none. If it has antigen, it is called as Rh+. If none it is Rh - . 

Blood type o- is considered as the universal blood because they can give it to people having different blood types without risking a transfusion reaction.