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-.
White blood cells. White blood cells are much less common than red blood cells. There are five types of white blood cell (leucocyte). These are divided into two main classes. 1  Granulocytes (includes Neutrophils, Eosinophils and Basophils). 2  Agranulocytes (includes Lymphocytes and Monocytes).ymphocyte. These are the second most common white blood cell (20-50%), and are easy to find in blood smears. Although the cells look similar there are two main types, B-cells and T-cells. B-cells develop in the bone marrow.