Complex sentence: All objects we see with the naked eye are composed of atoms and this atomic matter is in turn made up of interacting subatomic particles, usually a nucleus of protons and of neutrons, and a cloud of orbiting electrons.
Split into simpler sentences: All objects we see with the naked eye are composed of atoms. This atomic matter is in turn made up of interacting subatomic particles--usually a nucleus of protons and neutrons, and a cloud of orbiting electrons.