Answer : The correct option is, (D) Digesting a salad
Explanation :
Chemical change : It is a change where changes occurs in the chemical composition and thus resulting in the formation of new compound or substance.
Physical change : It is a change in which shape and size of a substance changes. In this there is no change in the chemical composition of the substance and no new substance is forming.
(A) Mixing a salad dressing : It is an example of physical change because in this compositions are same that means no changes in chemical composition.
(B) Dicing an onion : It is an example of physical change because there is no change in the chemical composition of the substance and no new substance is forming.
(C) Preparing a salad : It is an example of physical change because there is no change in the chemical composition of the substance and no new substance is forming.
(D) Digesting a salad : It is an example of chemical change because digestion is considered as chemical change in which an enzyme break down the larger molecule into smaller molecules so that our body can easily absorb food.
Hence, the example of chemical change is, (D) Digesting a salad