What is smallest living organism?

The smallest living organism known is a bacterium called Mycoplasma genitalium, which is only about 200-300 nanometers long. It is a type of bacteria that live in the human body and is associated with certain sexually transmitted infections. Despite its small size, it is a complete and functional organism with a distinct cellular structure and processes, including metabolism, growth, and reproduction. Other tiny living organisms include viruses, which are even smaller than bacteria and cannot reproduce without the help of a host cell.