A Pot of Room Temperature Water Is Placed on a Stovetop

A pot of room temperature water is placed on a stovetop burner.After a couple of minutes,small,odorless,colorless bubbles form and bubble out of the liquid.After a few more minutes,similar,larger bubbles form and bubble out at a faster rate.Which of the following is the best explanation of the observations?

A) No change occurs because the bubbles contain no matter.
B) The smaller bubbles are a result of a physical change, and the larger bubbles are the result of a chemical change.
C) The smaller bubbles are the result of a chemical change, and the larger bubbles are the result of a physical change.
D) Both the smaller and larger bubbles are the result of a physical change.
E) Both the smaller and larger bubbles are the result of a chemical change.