For court-martials, the statute of limitations is five years, except for any offense where the maximum permissible punishment is death, and for absent without leave (AWOL) or missing movement in time of war. In such cases, there are no statute of limitations.
Unlike today where many mitochondria and a cell coexist, mitochondria and cells were once separate organisms. Mitochondria were free-living bacteria that could produce energy, yet they struggled to protect themselves.
Some single-celled creatures have a nucleus, and some do not. Some single-celled plants have chloroplasts, but not all have stiff cell walls. All single-celled organisms eat, get rid of wastes, and reproduce. Single-Celled Organisms Amoebas, Algae, Plankton, and bacteria are single-celled organisms. You need a microscope to see single-celled organisms.