Answer: ELEMENT: Is a substance made up of same type of atoms having same atomic number. Eg: Na, Cl etc.
MIXTURE: Is a substance in which two or more than two substances combine together in a variable ratio. Eg: Air, Fizzy drink etc.
COMPOUND: Is a substance in which two or more than two substances combine together in a fixed ratio. Eg: H2O, CO2 etc.
Also unrelated but to the person who gave me a warning for my "plagiarism" me and my teacher made that page for your information and I was suggesting it to him because it wouldn't let me send links. You should think before you act because I did nothing wrong, and yes, this is targeted towards renardtnt1.