Combustion means the burning of something. So in the given question, you could say, “In this question, combustion means the burning of methane”.
Explanation:
option 2) voltaic cells only
<em><u>I </u></em><em><u>guess </u></em><em><u>so </u></em><em><u>this </u></em><em><u>is</u></em><em><u> </u></em><em><u>the </u></em><em><u>answer</u></em><em><u> </u></em><em><u>or </u></em><em><u>not </u></em>
Answer:
gravitation force is your answee
Many things could indicate that a chemical change has occurred. The release of a gas, or bubbling, etc. Just be careful not to mix it up with physical changes. A chemical change means that the chemical structure is different. You can reverse a physical change, but you cannot reverse a chemical reaction.