Class Notes NCERT Solutions for CBSE Students
Question: How is the balance of oxygen and carbon dioxide maintained in air?
Answer: The balance of oxygen and carbon dioxide in the atmosphere is maintained through respiration in plants and animals and by photosynthesis in plants. Plants produce oxygen during photosynthesis and utilize oxygen during respiration. They produce much more oxygen photosynthesis than they consume. During respiration this is how the oxygen consumed by plants and to a large extent by animals is replenished in the air through photosynthesis.
Question: Define pollution. How does air gets polluted?
Answer: The addition of substance in the environment in quantities that are harmful to living beings is called pollution. Air is getting polluted day by day because of various human activities:
- Burning of fuels like coal and petroleum, excessive burning of fuels like wood, smoke.
- Harmful gases released from industries.
- Smoke released by vehicles and machines releasing gases are the major causes of air pollution. These gases spread and mix in the air and spoil the quality if air, thereby making it impure.
Question: What are the major effects of air pollution on plants and animals?
Answer: Air pollution has major adverse effects on plants, animals as well as human beings. Harmful gases present in the polluted air make breathing difficult. Air pollution also leads to a lot of lung disease like asthma and lung cancer. Air pollution also damages crops.
Question: Name some of the ways by which we can reduce air pollution.
Answer: There are a number if ways by which we can reduce air pollution. Some of them are: Planting more and more trees, recycling plastics, regular checking of vehicles for emission of harmful gases etc.
