The substance which undergoes decomposition by the microbial action is called a:
Biodegradable substances are those materials or products that are able to naturally break down or decompose without causing any harm to the environment. Biodegradable substances are generally things that are organic in nature. This means they are substances that are made from things that were living at some point. Examples of biodegradable substances include paper which is made from trees, meat products which come from animals and leather products.