Question

what can we say about electrons?
they move around outside the nucleus.
they are in the nucleus and never leave.
they move in and out of the nucleus.

Explanation:

In atomic structure (a topic in Physics, a subfield of Natural Science), electrons are known to orbit around the nucleus in electron clouds or shells, not residing within the nucleus (protons and neutrons are in the nucleus). So the correct statement is "They move around outside the nucleus."

Answer:

They move around outside the nucleus.