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-.
There are 4 basic blood types. A, B, AB, and O. Then, there is the rh factor, determining if you are negative or positive. So, there is A+, A-, B+, B-, AB+, AB-, and O+, or â¦O-. O is typically the universal donor. That means that it is able to be taken by the other blood types IF you match the (+) or (-).