Answer:
1 cell
Step-by-step explanation:
Hence the name, single celled organisms, or unicellular organisms, (the prefix uni means one), single celled organisms only have one cell.
This single cell sustains life for the organism and carries out all the necessary processes.
Usually, these types of organisms are extremely tiny and can't be seen without a microscope. For example, bacteria and amoebas are single celled organisms.