(Submitted by the author)
When people think of the earth and of the terrestrial environment, they invariably associate it with the color green. But, as that famous photo of Planet Earth taken from space shows, this is a blue planet.
Earth is the only planet known to have water. It is, in fact, covered with water over nearly three-quarters of its surface. Oceans and rivers, ponds and streams, lakes and falls, glaciers and seas run like veins through a living body, carrying refreshment and nutrients to all its parts.