He Statue of Liberty is made out of copper and was once shiny and copper-colored. Over the years, the copper has gone through a process called oxidation, where it has changed into a new material. What has occurred?

an endothermic reaction
an energy formation
a chemical reaction
a precipitate formation

A chemical reaction.

Explanation:

A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.

Since the Statue of Liberty is made out of copper and was once shiny and copper colored. Over the years, the copper has gone through a process called oxidation, where it has changed into a new material. Thus, this is a chemical reaction.

answer; i believe that the correct answer is (a) potassium(k)