During digestion the body uses both physical and chemical changes to move and process food. Which of the following is an example of a physical change?

1.Teeth breaking food down into smaller pieces

2.Protein breaking down into amino acids in the stomach

3.Enzymes breaking down carbohydrates into simple sugars

4.Hydrochloric acid breaking down fats in the stomach

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.