We know that life on earth began with microorganisms. The micro-organisms evolved approximately 3.7 billion years ago through direct sunlight from the sun and water, as the ozone layer hadn’t formed till then. Because of microorganisms, not only did the existence of living beings appear on the earth, but they also created the nutrient-rich environment necessary for the living creatures. Even today, they exist and will continue to exist in every living being. Because actually, living beings exist because of these microscopic organisms.