Answer: A. Leaving Cheese out to get moldy
Step-by-step explanation:
A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions.
Example: Smelling Sprayed perfume : It is only diffusion of gas.
Feeling the ice melt on your skin: It is only change of state.
Crushing ice with a hammer: It is only change of shape.
A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions.
Example: Leaving Cheese out to get moldy : It involves oxidation of cheese to form new substances.
Thus Leaving Cheese out to get moldy is a chemical change.