Over time, flavors of ______beers change more quickly.

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.

A．The Mayas.
B．The Mochica Indians of Peru.
C．The Indians of Central Mexico.
D．The Indians of South Americ