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

Passage: Bacteria are responsible for many types of diseases in humans. Answer: diseases
Bacteria are responsible for many types of what in humans?

Passage: Greenhouse gases include CO 2 , H 2 O, methane, O 3 , nitrous oxides (NO and NO 2 ), and chlorofluorocarbons (CFCs). All are a normal part of the atmosphere except CFCs. The table below shows how each greenhouse gas naturally enters the atmosphere ( Table below ). Answer: greenhouse gases
Co 2 , h 2 o, methane, o 3 , nitrous oxides (no and no 2 ), and chlorofluorocarbons (cfcs) are known as what type of gases?

Passage: Some reactions need extra help to occur quickly. They need another substance, called a catalyst. A catalyst is a substance that increases the rate of a chemical reaction but is not changed or used up in the reaction. The catalyst can go on to catalyze many more reactions. Answer: a catalyst
What is the term for a substance that increases the rate of a chemical reaction but is not changed or used up in the reaction?