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.
Blood groups further classified as Rhâpositive or Rhânegative are called blood types. Blood is Rhâpositive if the. blood antigen labeled âDâ is present and it is Rhânegative if the âDâ antigen is absent. O+ is the most common blood type. Not all racial and ethnic groups have the same mix of these blood types. Hispanic people, for example, have a relatively high number of Oâs, while Asian people have a relatively high. number of Bâs.
Rare blood types are O negative and AB negative. B negative and AB  positive are also fairly rare blood types. O negative is known as  the universal donor blood type because â¦ it is compatible with any  other blood type.