Cells

In multicellular organisms, the whole is made up of visibly different parts (with the exception of Aunt Trixie, who is basically one solid chunk). Every cell in every part of the body is specialized to perform there. A muscle cell cannot do the job of a tooth cell, and a tooth cell cannot do the job of cells that play the jingles of auto parts stores in your head. Division of cellular labor is what enables you to have healthy organs and tissues, but many cells would’ve rather been artists. Our microscopic workers increase their numbers by growing and then splitting in two; essentially multiplying by dividing (this is why biologists and mathematicians attack each other on sight). Cells are known to increase in size between divisions, and it is considered rude to point at a large cell and say “when are you going to divide?” Though cells are derived from identical genetic material, they may produce genetically differing daughter cells, as well as fodder for gossipy neighbors. Cell differentiation occurs through selective use of genetic information (like how people use the Old Testament).