Question

What is an atom? and what 2 regions make up all atoms?

Answer 1

An atom is composed of two regions: the nucleus, which is in the center of the atom and contains protons and neutrons, and the outer region of the atom, which holds its electrons in orbit around the nucleus.

Answer 2

An atom is the smallest particle that cannot be split.
Two regions that make up an atom are the nucleus, that is in the center of the atom and contains protons and neutrons, and outer part of an atom that holds electrons.