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

[Q]: Passage: Oxygen is needed to make ozone. Ozone is a molecule made of three oxygen ions. Ozone in the upper atmosphere blocks harmful solar radiation from reaching the surface. Without oxygen, life on Earth would have been very simple. Answer: three
[A]: How many oxygen ions make up an ozone molecule?

[Q]: Passage: The power of the ocean modifies landforms by erosion and deposition. Landforms modified by both erosion and deposition are seen in this photo. The cliff is being eroded by incoming waves. The beach is being created as sand is being deposited. Answer: erosion and deposition
[A]: By what processes does the ocean modify landforms?

[Q]: Passage: Hydrocarbons are compounds that contain only carbon and hydrogen atoms. The smallest hydrocarbon, methane (CH 4 ), contains just one carbon atom and four hydrogen atoms. Larger hydrocarbons contain many more. Hydrocarbons with four or more carbon atoms can have different shapes. Although they have the same chemical formula, with the same numbers of carbon and hydrogen atoms, they form different compounds, called isomers . Isomers are compounds whose properties are different because their atoms are bonded together in different arrangements. Answer: isomers
[A]:
What do you call compounds whose properties are different because their atoms are bonded together in different arrangements?