Question

Why are some substances biodegradable and some non-biodegradable?

Answer 1

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.