Detailed Instructions: In this task, you're given a passage, further information available on a particular linked term from the statement, and an answer term. Your job is to generate a question that can use the information provided to obtain the given answer. You should use the information on both passage and link information to create the question. Note that the answer to the question should be exactly the given answer, and if the answer is none, the answer to the question shouldn't be obtainable from the passage or linked information.
Q: Passage: Starting fluid is a volatile, flammable liquid which is used to aid the starting of internal combustion engines, especially during cold weather or in engines that are difficult to start using conventional starting procedures. It is typically available in an aerosol spray can, and may sometimes be used for starting direct injected diesel engines or lean burn spark engines running on alcohol fuel. Some modern starting fluid products contain mostly volatile hydrocarbons such as heptane, (the main component of natural gasoline) with a small portion of diethyl ether, and carbon dioxide (as a propellant). Some formulations contain butane or propane as both propellant and starting fuel. Historically, Diethyl ether, with a small amount of oil, a trace amount of a stabilizer and a hydrocarbon propellant has been used to help start internal combustion engines because of its low autoignition temperature.
Link Information: carbon dioxide (as a propellant) Answer: Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms.
A:
What is the chemical composition of the propellant?