The correct answer is D. The nucleus and the electron cloud
Explanation:
An atom is the smallest particle that composes all matter in the universe. Atoms are composed of three main sub-particles: neutrons, protons (positively charged), and electrons (negatively charged). Additionally, the neutrons and protons are in the center of the atom and form the nucleus that has a positive charge due to the protons, while the electrons negatively charge are not in the nucleus but orbit as part of electron clouds that surround the nucleus. Thus, the two parts of an atom are the nucleus that contains protons and neutrons and the electron cloud that contains electrons.
