b) Heat is lost by the water droplets. When they condense on the surfaces, they turn from gas to liquid state. This change requires the water droplets to lose heat, therefore heat is lost by the water droplets.

c) Replace the water with room temperature water and the lid with a chilled one instead. Since the surface of the glass is not cooler than the surrounding air, water will not condense on the walls. However, a chilled lid has a cooler surface area for the water vapor in the air to condense on, hence forming water droplets.