Biodegradable orenvironmentally preferable product is often associated with environmentally friendly products and being able to be broken down by natural processes, into more basic components. Products are usually broken down by bacteria, fungi or other simple organisms. By this definition, most chemicals are biodegradable; the only thing differing would be the amount of time it takes to break down. A piece of bread will break down rather quickly, whereas a piece of plastic will take decades and beyond.
Rate of breakdown may not be as important as what the product breaks down into. The ideal final products of any complex product of Carbon, Hydrogen, and Oxygen would be Carbon Dioxide (CO2) and Water (H2O). A majority of products are made mostly of these three elements. The previously mentioned piece of bread is made mostly of these, and after breaking down from complex sugars to simpler sugars, will eventually degrade to CO2 and H2O. This process would be accelerated if we ate the bread and our body would break it down and use it as energy, until only CO2 and H2O are left.
Source: www.ecomall.com