Short Questions: Air Around Us | NCERT Summary: UPSC PDF Download

Q1: Why do mountaineers carry oxygen cylinders while climbing high altitudes?
Ans: The atmosphere thins out at high heights. As a result, the amount of oxygen available at high elevations will decrease and at high elevations, there will be less oxygen available for breathing and respiration. Therefore, mountaineers carry oxygen cylinders in order to breathe efficiently.

Q2: How is oxygen in the atmosphere replaced?
Ans: Organisms utilise oxygen for their respiration. Because all living species require oxygen to breathe, the oxygen level will drop. The action of photosynthesis replaces oxygen in the atmosphere. The process by which plants produce food is known as photosynthesis. In the presence of sunlight and chlorophyll, plants use carbon dioxide and water to make glucose and oxygen. This process produces oxygen, which is then released into the atmosphere.

Q3: Why do earthworms come out of the soil during heavy rains?
Ans: There are spaces in the soil where air can be found. Animals that dwell in the soil need the air contained in the soil spaces to breathe. During severe rains, all of these air spaces are filled with water, making it impossible to breathe. That is why, following heavy rains, soil dwellers such as earthworms emerge from the soil to get oxygen directly from the air.

Q4: Why does burning a fire in a closed room cause suffocation?
Ans: Any fuel that is burned consumes the oxygen in the room and produces carbon dioxide. Because the chamber is closed, neither new oxygen nor accumulated carbon dioxide can enter or exit. As a result, we have less oxygen to breathe and more carbon dioxide enters our bodies. Carbon dioxide is poisonous to our bodies, and because there is less oxygen available for breathing when carbon dioxide is burned in a closed space, asphyxia occurs.

Q5: Why should we breathe through the nose and not the mouth?
Ans: Our nose contains two nostrils, each coated with a dense layer of tiny hairs. These hairs filter the air we breathe in, removing dust and smoke particles. As a result, dangerous airborne particles do not reach our bodies. Because our mouths lack such a filtering mechanism, breathing via our mouths increases the odds of dangerous dust and smoke particles entering our lungs.