What defines a mixture? a) a mixture contains different substances that are chemically combined. b) a mixture contains different substances that are not chemically combined and can be broken down into its basic substances through physical means. c) a mixture is created through a chemical reaction.

B is your best answer because a mixture is when two or more things combine but not chemically. Take soup for example you take out all the pieces because they didn't combine together and just become 1 thing they still have parts. You can still take the noodles, you take the fish or meat out still, you take the broth away to.