What is in between electrons?

Question

If the electron is the smallest possible unit of matter, what is in between them and what is that made up of?

Answer 1

In between electrons is just space and actually there are units of matter that are smaller then matter called quarks and there is also a theory that there are things smaller then quarks called strings.

Answer 2

Between the nuclei of atoms and the electrons orbiting them, there is just empty space.