Question

why are some substances biodegradable and some non-biodegradable?

Answer 1

Substances that are broken down by biological processes are said to be biodegradable. In our environment, many of the substances are broken easily by decomposers (bacteria and fungi) as they possess specific enzymes for such activity. However, there are other substances also which are not broken down in this manner and are known as non-biodegradable substances. Since these substances are not degraded by bacteria and fungi, so they persist for a long time. These non-biodegradable substances will be acted upon by physical processes like heat and pressure.

Answer 2

Some substance are biodegradable and some are biodegradable because there are substances that are decomposed naturally by the microorganisms present in the environment.The organic substances are easily decomposed by the decomposers .Like any small animals which died is being eaten up by the microorganisms (putryfying bacterias) and there is no remains of the animals.

The main reason of a substance being biodegradable is being organic that can be used up by scavengers of environment. On the other hand some substances are non biodegradable because they are synthetic and cannot be decomposed by the microorganism.