When a sample of gas is cooled, it condenses into a liquid. In which of the following ways do the molecules of the original gas sample compare with the molecules of the liquid?

a. The molecules weigh less as a gas than they do as a liquid.
b. The molecules are larger as a gas than they are as a liquid.
c. The molecules are closer together as a gas than they do as a liquid.
d. The molecules move faster as a gas than they do as a liquid.