Watch Water Makes Life Possible/The Water Cycle

Program 1: Virtually all life depends on the water molecule. Water composes 70% of mammalian and human body structures. Our cells are largely hydrologic, and most body functions depend on water to work properly, including respiration, digestion, and waste disposal. Program 2: The water cycle influences all aspects of biological and human systems. Only 1% of Earth's freshwater is readily available for life, making water conservation more difficult and more important than ever. Explore how Earth changed from life-forbidding heat into a planet covered by more water than land, making life possible.