34154
When " z " falls below roughly 50 % of the stoichiometric value , Methane can become an important combustion product ; when " z " falls below roughly 35 % of the stoichiometric value , elemental carbon may become stable .
 Methane
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Methane