Micro-orgasims are very small particles that you can see under a microscope.
Microorganisms are typically too small to be seen with the naked eye, often requiring a microscope for visualization. While some microorganisms, like certain bacteria and fungi, can produce odors due to metabolic byproducts, most are odorless. Therefore, while you cannot see them without magnification, you may sometimes detect their presence through smell.
Decomposition occurs because of oxygen and bacteria. Without decomposition the earth would become dry and lifeless. It a series of things that happen. Like the food chain if one fails they all.