The answer is Bacteria
Prokaryotes are a microscopic single Celled organisms that has neither a distinct nucleus with a membrane nor other specialized organelles.
In a solar system, there is a sun that is in the middle and has planets orbiting around it. The same way, the nucleus is in the middle with electrons orbiting the nucleus. <span />
The movement of substances (as by diffusion) across a cell membrane without the expenditure of energy.
