Over time, flavors of ______beers change more quickly.

A．it may not carry an expiration date
B．it loses it potency completely in three months
C．its efficacy decreases over time if kept in extreme heat
D．it is a lotion that may protect your skin from ultraviolet radiation

A．Soft, porous rock being worn away by a waterfall.
B．Water depositing minerals on the banks of a gorge through which the water runs.
C．Trapping of water in a sealed underground rock cavern due to an earthquake.
D．Water becoming unfit to drink through the release of pollutants into it from a plant.