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: When light passes from one medium to another, it changes speed.

Answer: When light passes from one medium to another, it changes what?


Question: When the energy of the earthquake reaches shore, it forms a huge wave called a tsunami.

Answer: When the energy of the earthquake reaches shore, it forms a huge wave called?


Question: Hydrocarbons are combined with oxygen in a series of enzymatic steps to product water, carbon dioxide, and energy, which is stored in the form of reactive molecules.

Answer:
Hydrocarbons are combined with oxygen in a series of enzymatic steps to product water, carbon dioxide, and energy, which is stored in the form of what?