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-.
O Negative blood is the fifth most rare type. 1 in every 15 people are born with O Blood (About 6.6% of the population) B positive blood is the sixth most rare type. 1 in every 12 people are born with B+ Blood (About 8.5% of the population) O Positive blood is the seventh most rare type.