Why are some substances biodegradable and some non-biodegradable?
Substances are classified as biodegradable and non-biodegradable because some substances can be decomposed by microorganisms and some cannot.
Substances that are broken down into simple soluble forms are called biodegradable substances
For example: Cotton, wood, paper, wool, etc.
the substances that are not decomposed by microorganisms into harmless substances are called non biodegradable substances.
For example: Plastic, polythene, DDT, etc.