Write a correct answer to the given question based on its associated fact. Make sure that your answer is contained in the associated fact. Don't be creative and introduce any new word that is not mentioned in the associated fact! Remember that the associated fact has been rearranged to form the question. So, the correct answer words must lie within the associated fact. The correct answer can be a word, phrase, or even a sentence.
--------
Question: Fact: barometric pressure makes clear weather. 
Question: What causes clear weather?

Answer: barometric pressure.


Question: Fact: oxygen is essential for cellular respiration for fungi. 
Question: what requires oxygen for cellular respiration?

Answer: fungi.


Question: Fact: automobile engines burn gasoline to convert the fuel's energy into mechanical energy. 
Question: Why do automobile engines burn gasoline?

Answer:
Automobiles burn gasoline to release the chemical energy of the fuel to provide mechanical energy.