ABSTRACT
Water that falls on the land is absorbed by the roots of plants, passed through their stems and other structures, and released from sto mata in their leaves into the atmosphere as water vapor by transpiration. Through runoff, water moves from the land to water bodies and into the ground, where it is stored as ground water. From there, it eventually returns to the surface, lakes, streams, or oceans. Human activities can adversely affect the quality and
quantity of water. Water quality is degraded by agricultural runoff or by overloading a water supply with wastes, such as from wastewater treatment plants or factories. Water quantity to different regions may be affected if global pre cipitation patterns are altered through climate change (see Section B).
