Which substance can not be broken down by a chemical change

ay just use soratic or whatever its called you'll get the answer the image is a owl

because natural gas is colorless, odorless, and tasteless, distributors add mercaptan (a chemical that smells like sulfur) to give natural gas a distinct unpleasant odor (it smells like rotten eggs). they locate the types of rock that are likely to contain natural gas deposits.