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: space exploration is not possible without navigation. 
Question: What is used for space exploration?

Answer: navigation.


Question: Fact: blood traveling to the heart is deoxygenated. 
Question: Blood traveling to the heart is?

Answer: deoxygenated.


Question: Fact: heat and pressure change the remains of dinosaurs into natural gas. 
Question: What does heat and pressure change into natural gas?

Answer:
remains of dinosaurs.