Final answer:
Cells are the smallest and most basic units of life, enclosed by a membrane, and visible under microscopes like the electron microscope. They are the fundamental unit of life and new cells come from existing ones
Step-by-step explanation:
The smallest and most basic units of life are known as cells. These are microscopic, self-contained units that are enclosed by a water-repelling membrane. Members of the scientific community use various types of microscopes, such as electron microscopes, to achieve higher magnification and resolution to study these tiny units of life in greater detail.
According to the unified cell theory, all organisms are composed of one or more cells, the cell represents the basic unit of life, and new cells arise from existing cells. Prokaryotic cells, such as those found in domains Bacteria and Archaea, are single-celled organisms without membrane-bound organelles or nuclei.