Our Earth the only one planet known to support life.Human interventions cause continuous change in the natural environment.What is nature.How natural environment is altered.Why such alterations go beyond limit and in what ways they affect us.This is an environmental treatise.
Our small intestine is 17 meters long and 2.5 centimeters in diameter.Actual total area is equal to the size of a tennis court(250 square meter).Sea urchin, lung fishes, and platypus have no stomach.
