Question

which of these is an example of a chemical change?
all of these
a piece of bread growing mold
a banana turning brown when exposed to the air
baking a cake

Explanation:

A chemical change results in a new substance with different properties. Bread growing mold involves biological - chemical reactions creating new substances. A banana turning brown is due to oxidation, a chemical reaction. Baking a cake causes chemical reactions like the denaturation of proteins and the Maillard reaction, creating new substances.

Answer:

A. All of these