Which of the following make up the nucleus of an atom? A. protons and neutrons B. electrons only C. neutrons only D. protons and electrons

Answer: A. protons and neutrons

Explanation: An atom is smallest unit of a matter or a substance. Every atom consists of three subatomic particles : electrons, protons, neutrons.

Protons and Neutrons are located in the center of an atom where while mass of an atom is concentrated.

Atomic mass = Number of protons + Number of neutrons

Electrons are located outside the nucleus where they orbit in different energy levels around the nucleus.

A) protons and neutrons