Given a scientific passage and an answer, generate a question for the given answer.

Input: Consider Input: Passage: Nuclear changes occur with a simultaneous release of energy. Where does this energy come from? If we could precisely measure the masses of the reactants and the products of a nuclear reaction, we would notice that the amount of mass drops slightly in the conversion from reactants to products. Consider the following nuclear reaction, in which the molar mass of each species is indicated to four decimal places:. Answer: energy

Output: Nuclear changes occur with a simultaneous release of what, and a slight drop in mass?

Input: Consider Input: Passage: When electrons are removed from an atom, that process requires energy to pull the electron away from the nucleus. Addition of an electron releases energy from the process. Answer: energy

Output: What is required when electrons are removed from an atom, and released from the process when an electron is added?

Input: Consider Input: Passage: Changes in the genes of a species may result in a new species. This is biological evolution. Answer: biological evolution
Output: When changes in the genes of a species result in a new species, the process is called what?