Final answer:
The cell theory development was assisted by advancements in microscopes and the invention of the electron microscope. The statement 'A one-celled organism is not a living thing' is false according to the cell theory.
Explanation:
The development of the cell theory was aided by:
- building the first microscopes,
- making more advanced microscopes, and
- the invention of the electron microscope.
Explanation for the false statement:
The statement 'A one-celled organism is not a living thing' is false according to the cell theory because all living things are made up of one or more cells, and the cell is the basic unit of life as proposed by the unified cell theory.
Learn more about Cell Theory and Microscopy here:
https://brainly.com/question/36954200