Is the yellowing of the pages of an old book a physical or chemical change? please explain​

a chemical change. A physical change would be like crushing up a piece of paper, you could fold it back out until its flat. A chemical change would be something unreversable, i.e. going from all the different ingredients to a fully b asked cookie. The yellowing of pages is due to oxidization.

Explanation:

a polar bond is formed when electrons are shared unevenly between atoms