Mario claims that a chemical reaction occurs when the yeast, water, and hydrogen peroxide are combined. Which observation BEST supports his claim?

The mass of the yeast-water-hydrogen peroxide mixture is different from the mass of the elephant toothpaste.
The temperature of the yeast-water-hydrogen peroxide mixture is the same as the temperature of the elephant toothpaste.
The chemical properties of the yeast-water-hydrogen peroxide mixture are the same as the chemical properties of the elephant toothpaste.
The physical properties of the yeast-water-hydrogen peroxide mixture are different from the physical properties of the elephant toothpaste.

The physical properties of the yeast-water-hydrogen peroxide mixture are different from the physical properties of the elephant toothpaste.

This observation supports Mario's claim because a chemical reaction often results in a change in physical properties of the substances involved. In this case, the yeast, water, and hydrogen peroxide reacting to create elephant toothpaste would result in a different physical appearance compared to the initial mixture.