NCERT Solutions for Class 10 Science Chapter 15 Our Environment

Decomposers break down the organic components of dead and decaying matter into simple inorganic substances. The organic matter like dead animal bodies are recycled in the ecosystem thereby cleaning the environment. And, the inorganic elements return back the minerals into the soil making the soil fertile. Thus, decomposers play a vital role in the ecosystem.

Substances that can be broken down by biological processes are said to be biodegradable. In our environment, many of the substances are broken easily by decomposers. Examples: Paper, vegetable peels etc.
However, substances which cannot be broken down biologically but by physical means are known as non-biodegradable substances. Example: Plastic.

Ozone (

) is a molecule formed by 3 oxygen atoms. Ozone is present in the stratosphere shielding the earth’s surface from the harmful UV rays by absorbing it.
Ozone may affect the ecosystem in the following ways:
1. If this layer gets depleted, the UV rays can cause cancer in human beings and also some plants and animals.
2. The UV rays may effect the plants and destroy the vegetations.

Two methods used to reduce the problems of waste disposal are:
Throwing biodegradable and non-biodegradable waste into separate dustbins so that recycling can be done easily.
By putting the organic waste into compost pits dug in the ground and preparing compost. This compost helps in increasing the fertility of soil.
Practicing the 3 R’s: Reduce, Reuse and Recycle.