9781422280539

Chapter 1 The Basis of Life

W ords to U nderstand aquatic: relating to things located in or near water. electrolyte: a mineral in the body that is able to conduct an electric charge. hydration: the act of combining a substance with water; to add water to the body. hydrologic cycle: the continual circulation of water between land

or water surfaces on Earth and the atmosphere. lubricate: to make something move smoothly. metabolites: the products of chemical reactions that occur within living organisms. perspire: to release sweat through the pores of the skin, due to heat, physical activity, or other stresses. solvent: something that can dissolve other substances. I t covers 70 percent of the planet and makes up over half of your body weight. In one way or another, it is vital to the health and sustenance of all life on Earth. Plants need it to produce oxygen, fish and other ocean animals rely on it for their habitat, and humans need it to grow food. Without it, the cells of living organisms could not take in nutrients or shuttle out toxins. It’s so crucial, in fact, that when scientists are looking for life on other planets, they check to see if it’s there first. The name of this incredible substance? Water.

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