When you squeeze an air filled party balloon, you increase its b mass.
Explanation: Squeezing the balloon does not allow the air inside to escape, but it compresses the air molecules closer together. As you compress the balloon, you change the shape and size of the balloon (its volume), but the amount of air (its mass) remains the same if none escapes. While the weight of the balloon remains constant because the mass has not changed, the density increases as you compress the air. However, in answer to the question, the mass of the air remains the same despite the squeezing of the balloon.