A complex number can be visually represented as a pair of numbers (a, b) forming a vector on a diagram called an Argand diagram, representing the complex plane. Re is the real axis, Im is the imaginary axis, and i is the imaginary unit which satisfies i2 = â1.
When discussing blood types, the two groupings most commonly used are the ABO (A, B, AB, O) and Rh (+, -) systems. The least common blood type in humans is Bombay (EXTREMELY râ¦are), which is a type O with missing H antigen. Otherwise, of the normal ABO and Rh typings, the least common group is AB-.
More than just two blood types are not compatible with each other. The four basic types of blood are: A, B, AB, O(not counting Rh).Type A blood can only receive blood from type A and type O. However, type A blood can donate their blood to type A and type AB. Because if a person needs a blood transfer, it MUST be from a donor with a compatible blood type. Otherwise, the transfer will kill the recipient. More elaborately, bl â¦ ood types are determined by the presence of two types of compounds in the blood.