Given a scientific passage and an answer, generate a question for the given answer.
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Question: Passage: Elements and Compounds Any sample of matter that has the same physical and chemical properties throughout the sample is called a substance. There are two types of substances. A substance that cannot be broken down into chemically simpler components is an element. Aluminum, which is used in soda cans, is an element. A substance that can be broken down into chemically simpler components (because it has more than one element) is acompound (Figure 1.2 "The General Steps of the Scientific Method"). Water is a compound composed of the elements hydrogen and oxygen. Today, there are about 118 elements in the known universe. In contrast, scientists have identified tens of millions of different compounds to date. Answer: substance

Answer: Any sample of matter that has the same physical and chemical properties throughout the sample is called what?

Question: Passage: Saturated hydrocarbons contain only single bonds between carbon atoms. They are also called alkanes. They may form straight-chain, branched-chain, or cyclic molecules. Compounds with the same number of atoms but different shapes are called isomers. Answer: alkanes

Answer: What is another word for saturated hydrocarbons?

Question: Passage: Deposition as a change of state often occurs in nature. For example, when warm moist air comes into contact with very cold surfacessuch as the ground or objects on the groundice crystals are deposited on them. These ice crystals are commonly called frost. Look at the dead leaf and blades of grass in the Figure below . They are covered with frost. If you look closely, you can see the individual crystals of ice. You can watch a demonstration of frost forming on the side of a very cold can at the URL below. (Click on the mulitmedia choice "Ice on a Can. "). The ice in the can has been cooled to a very low temperature by adding salt to it. If you want to do the demonstration yourself, follow the procedure at the URL. http://www. middleschoolchemistry. com/lessonplans/chapter2/lesson4. Answer: frost

Answer:
What are the ice crystals that form on the ground called?