Ascientist isolates a single celled organism from the bottom of a sulfur hot spring. when examined under the microscope, it is clear that the cell is very small and contains no nucleus. based on this evidence alone, in what domain of life is this organism

The organism can be classified into the domain Archaea.

The scientist isolated a single celled organism from the bottom of a sulfur hot spring and when examined under the microscope, the cell was very small and had no nucleus.  Archaea are the organisms which live in extreme conditions and are called the extremophiles. They can tolerate high temperatures and survive in hot springs, anaerobic conditions and are acid-tolerant. The cells are very small and are similar to bacteria in lacking a nucleus and membrane bound organelles. The cell membrane is bound by a cell wall. They reproduce by binary fission, fragmentation or budding.

the generally accepted parts of modern cell theory include: all known living things are made up of one or more cells. all living cells arise from pre-existing cells by division. the cell is the fundamental unit of structure and function in all living organisms.