9. Which best accounts for the variety of cells within our bodies?

"The variety of cells within our bodies" is best accounted for by their variety of functions.

Explanation:

Body has various types of cells. Under a microscope, although they will feel different, many cells have similar chemical and structural characteristics. There are around 200 different cell types in humans, and there are about 20 different types of frameworks or organelles within those cells.

There are 4 major tissue kinds: connective, muscle, nervous and epithelial. Such tissues are constructed of specialized cells and grouped according to their respective structure and function. Although if new cells are formed then old one die too i.e between 50-70 B cells die per day in an average adult.