(a) We must use cotton clothes during summer.
1. During summer we sweat more due to high temperature.
2. Cotton clothes absorb sweat.
3. Synthetic clothes are water repellent.
They do not absorb sweat and we feel uncomfortable.
Hence,
We must use cotton clothes in summer.
(b) We must observe economy in the use of materials.
1. Due to excessive use of natural substances by human beings to fulfil their needs;
They are getting depleted at a faster rate.
2. At the same time,
It takes a very long time for these substances to get naturally formed again.
3. Hence,
We must observe economy in the use of materials so that they are available for the future generation also.
(c) Saving paper is the need of the hour.
1. Saving paper means saving trees as wood is used as the raw material to manufacture paper.
2. Trees are natural habitat for many Living things.
3. Trees help in increasing rainfall and water availability.
Hence,
Saving paper helps in saving trees which in turn maintains balance in nature.
(d) Man-made materials have more demand.
1. Man-made substances are waterproof, lightweight and easy for transportation.
Substances in Daily Use
2. They are easier to use and can be made available in plenty at a low cost.
Hence,
There is more demand for man-made materials.
(e) Humus is a natural material.
1. Humus is obtained from plant and animal wastes.
2. Micro-organisms act on these wastes and convert them into humus.
3. Hence, humus is a natural material.
