Answer & Explanation
A) A & B
A) Cooking of Food ------ Chemical Change
B) Digestion of Food ----- Chemical Change
C) Freezing of water ----- Physical Change
D) Water is heated up ---- Physical Change
because here the chemical composition of the substance changes in A & B only.
Since we know that, If the chemical composition is changing then it is a chemical change and if the chemical composition is remaining the same, then it is a physical change.