Which of the following is a physical change?

The correct answer is option 4. Crystallization.

Crystallization is an example of a physical change.

1. Digestion of Food in Our Body:

Digestion is a chemical change. It involves the breakdown of complex food molecules into simpler substances by enzymes and acids in the digestive system.

2. Ripening of Fruits:

Ripening of fruits is generally considered a chemical change. It involves the conversion of starches into sugars, changes in color, and alterations in texture, all driven by enzymatic processes.

3. Fermentation of Grapes:

Fermentation is a chemical change. It is a biological process in which sugars are converted into alcohol and carbon dioxide by microorganisms like yeast.

4. Crystallization:

Crystallization is a physical change. It involves the formation of solid crystals from a liquid or gaseous state. It does not involve a change in the chemical composition of the substance.

Therefore, the correct answer is Crystallization is a physical change.