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

Input: Consider Input: Passage: Water is the main ingredient of many solutions. A solution is a mixture of two or more substances that has the same composition throughout. Some solutions are acids and some are bases. To understand acids and bases, you need to know more about pure water. In pure water (such as distilled water), a tiny fraction of water molecules naturally breaks down to form ions. An ion is an electrically charged atom or molecule. The breakdown of water is represented by the chemical equation. Answer: solution

Output: What is the term for a mixture of two or more substances that has the same composition throughout?

Input: Consider Input: Passage: Connective tissue consists of cells that form the body's structure. Examples include bone and cartilage, which protect and support the body. Blood is also a connective tissue. It circulates and connects cells throughout the body. Answer: connective

Output: What tissue consists of cells that form the body's structure?

Input: Consider Input: Passage: The stratosphere is the layer above the troposphere. Temperature increases with altitude in this layer. The ozone layer occurs here. Answer: stratosphere
Output: What is the layer above the troposphere?