Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
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Question: People stopped adding lead to gasoline because of environmental pollution.

Answer: Why did people stop adding lead to gasoline?


Question: Seeds of a pine cone are easily carried by the wind and dispersed because seeds have wings.

Answer: Why are seeds of a pine cone easily carried by the wind and dispersed?


Question: Ozone is a compound formed when there is sparking electrical equipment.

Answer:
What compound is formed when there are sparking electrical equipment?