Deserts

"Scientists define a desert as a region that each year loses more water into the air as water vapor than it receives as precipitation in the form of rain, snow, sleet, hail, dew, or frost. Deserts may seem hostile to life, but most natural deserts are home to plants and animals that have adapted to flourish in the harsh environment. The expansion of deserts due to pollution or unsustainable farming practices presents a major ecological challenge for modern societies"--Back cover.