Which of the following are the three parts of an atom?

The three fundamental parts of an atom are protons, electrons, and neutrons. Protons are positively charged particles found in the nucleus of the atom, and they determine the atomic number, which defines the element. Neutrons, which are neutral particles, also reside in the nucleus and add to the atomic mass without affecting the charge. Electrons are negatively charged particles that orbit the nucleus in defined energy levels or shells.

This structure is foundational to understanding atomic theory and chemistry. The protons and neutrons contribute to most of the atom's mass, while electrons play a critical role in chemical interactions.

Other options include components that don't accurately represent the three primary parts of an atom. Isotopes, for example, are variations of elements based on the number of neutrons but are not a fundamental part of atomic structure. Quarks and electron clouds relate to more advanced concepts in particle physics and atomic structure, but they are not one of the three main particles that compose an atom. Similarly, orbits refer to the pathways of electrons around the nucleus rather than being parts of the atom itself.