Which of the following is not a physical change?
a. grating cheese
c. fermenting of cheese
b. melting cheese
d. mixing two cheeses in a bowl

Answer : Fermenting of cheese is not a physical change.

Explanation :

Physical change : Physical change is a change in which no new compounds are formed only changes occurs in size or state of substance. In this, there is no changes in the substance or compound.

Chemical change : Chemical change is a change in which a new compounds are formed by the chemical reaction. Changes occurs in their chemical composition and properties.

In grating cheese, only changes occurs in size of the substance. So, this is a physical change.

In melting cheese, only changes in the state ( solid to liquid). So, this is also a physical change.

In mixing two cheeses in a bowl, the composition of the substance is same, no new compounds are formed. So, this is a physical change.

In fermenting of cheese, a new substance is form by the chemical reaction. So, this is a chemical change.

Fermentation is chemical process in which substances are breakdown chemically by the bacteria, yeast or microorganism and it leads to the formation of a new compound.