Answer:
chemical change
Explanation:
turning methane plus oxygen into carbon dioxide and water is a chemical process because the substances change into completely new substances (co2 and water), it's no longer methane and oxygen. It's not a physical change because physical changes only affect appearance.
If this was a lab, possible evidences of a chemical change can be bubbling, heat, color change (occasionally)... etc.
chem isn't my best course but I hope this helps
