Which sentence best describes part of the process for generating electricity in a nuclear power plant? a. atoms join together to produce water molecules. b. an atom releases electrons, producing an electric current. c. protons and neutrons join together to create atoms. d. heat is released when atomic nuclei split.

Answer is: D. Heat is released when atomic nuclei split.

Nuclear fission is a nuclear reaction or a radioactive decay where nucleus of atom split into smaller ligher nuclei.

Nuclear fission is exothermic reaction which release large amounts of energy (electromagnetic radiation or as kinetic energy, which heat reactors where fission reaction take place).

Nuclear energy is the energy found in the nucleus of an atom.