Given a scientific passage and an answer, generate a question for the given answer.
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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: The cell membrane is made up of a phospholipid bilayer, two layers of phospholipid molecules. Notice the polar head group of the phospholipid is attached to the phosphate, and the tails are two fatty acid chains. The head group and tails are attached by a glycerol backbone. Answer: cell membrane

Answer: What basic cell structure is made up of a phospholipid bilayer and two layers of phospholipid molecules?

Question: Passage: The presence of solute particles blocks some of the ability for liquid particles to evaporate. Thus, solutions of solid solutes typically have a lower vapor pressure than the pure solvent. Answer: evaporate

Answer:
The presence of solute particles blocks some of the ability for liquid particles to do what?