Physical And Chemical Changes

The formation of curd from milk is a chemical transformation. This process involves the fermentation of lactose by bacteria, producing lactic acid, which causes the milk to thicken and form curd. This transformation alters the chemical composition of the milk, making it a chemical change. - Melting of ice and formation of ice are physical changes, as they only involve a change in the state of matter. - Melting of wax is also a physical change, as the substance returns to its original form once cooled. Thus, the correct answer is C (Formation of curd from milk).