Throughout history, many unscientifically based claims have been made. One such claim was that some people believed that fleas actually came from dust. Which part of the cell theory
provides a basis for disproving this claim?

There are no options to this question, however, it can be answered. The answer is:

All cells arise from previously existing cells

Explanation:

The universal cell theory was proposed in 1830's by three scientists viz: Rudolf Virchow, Mathias Scleiden, and Theodor Schwann. The cell theory consists of three major components which are generally accepted and used till date. The components are:

- All living things are made up of one or more cells

- The cell is the fundamental and basic unit in every living thing.

- All cells arise from previously existing cells via cell division

According to this question, many unscientifically based claims including the believe that fleas actually came from dust have been made. This claim has been DISPROVED by the part of the cell theory that states that "All cells arise from previously existing cells via cell division". Hence, fleas do not arise from dust but from other cells according to cell theory.