A weather balloon is released at sea level where the pressure is 1 atm and the temperature is 290 K. As it rises to an altitude where the pressure is 0.7 atm and the temperature is 270 K, what happens to the volume of the balloon?

• A. The volume remains constant.
• B. The volume decreases.
• C. The volume fluctuates.
• D. The volume increases.

Answer: (D)