A membrane bound nucleus (or just a nucleus in general)
Antibodies to common microorganisms have been developed by infancy. <span>An </span>antibody<span> (Ab), also known as an immunoglobulin (Ig), is a large, Y-shaped protein produced mainly by plasma cells that is used by the immune system to identify and neutralize pathogens such as bacteria and viruses.</span>
for instance in humans, the somatic cells include 46 chromosomes which is the diploid wide variety (2n) and each sperm and egg has 23 chromosomes wherein one of them is the sex chromosome.