Given a scientific passage and an answer, generate a question for the given answer.
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Question: Passage: The strength of bases is measured on a scale called the pH scale, which ranges from 0 to 14. On this scale, a pH value of 7 indicates a neutral solution, and a pH value greater than 7 indicates a basic solution. The higher the pH value is, the stronger the base. The strongest bases, such as drain cleaner, have a pH value close to 14. Answer: ph scale

Answer: The strength of bases is measured on what scale?

Question: Passage: Sperm ( Figure below ), the male reproductive cells, are tiny. In fact, they are the smallest cells in the human body. What do you think a sperm cell looks like? Some people think that it looks like a tadpole. Do you agree?. Answer: sperm

Answer: What are the male reproductive cells called?

Question: Passage: If you are painting indoors, there are more important concerns than just getting messy. You should also be concerned about breathing in the fumes from the paints. Making sure to get plenty of fresh air while painting is very important. Paint fumes can have serious health effects. Paint fumes are just one example of indoor air pollution. Answer: paint fumes

Answer:
Give an example of air pollution while painting indoors.