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

Input: Consider Input: Passage: A single-replacement reaction is one in which an element replaces another element in a compound. An element is in either the solid, liquid, or gas state and is not an ion. The example below shows the reaction of solid magnesium metal with aqueous silver nitrate to form aqueous magnesium nitrate and silver metal. Answer: single-replacement reaction

Output: In this type of reaction, an element replaces another element in a compound, and the element is in any state of matter but is not an ion?

Input: Consider Input: Passage: Solutes change the physical properties of solvents. They lower the freezing point and raise the boiling point of solvents. Answer: solutes

Output: What change the physical properties of solvents?

Input: Consider Input: Passage: In a red supergiant, fusion does not stop. Lighter atoms fuse into heavier atoms. Eventually iron atoms form. Answer: iron
Output: Atoms of what element ultimately form in a red supergiant?