can anyone give me any best site of bio chapter 6 natural resources notes NCERT.please
Answers
Answer:
atmosphere different form the atmospheres on Venus and Mars?
Ans. Our atmosphere contains gases like nitrogen, oxygen, carbon dioxide, water vapour and other gases in very small amount. Atmosphere of Venus and Mars have about 95% of carbon dioxide.
So life is not possible.
Q2. How does the atmosphere act as a blanket?
Ans. The atmosphere acts as a blanket in the following ways:
(1) It maintains the temperature on the surface of earth during day and night time.
(2) It contains Ozone in the upper layer which protects life from harmful ultraviolet radiation.
Q3. What causes winds?
Ans. The uneven heating of the atmosphere in different regions of the earth causes wind. The rotation of earth and presence of mountain ranges also helps in the formation of wind, its blowing direction.
Q4. How are clouds formed?
Ans. During day time water from different sources like pond, lake, river, sea, well etc get evaporated and this water vapour rises up with the hot air. At a particular height the air cools and the water vapour condenses to form minute droplets and form clouds. When these water-drops become heavy, they precipitate and fall down as rain.
Q5. List any three human activities that you think would lead to air pollution.
Ans. Three human activities which leads to air pollution are:
(1) Burning of fuels like coal, petroleum, kerosene.
(2) Smoke released from industries
(3) Emissions from vehicles.
NCERT TEXTBOOK PAGE 194
Q1. Why do organisms need water?
Ans. Organisms need water for the following activities:
(1) All cellular processes occur due to water.
(2) Transportation of substances in our body takes place by dissolving in water.
(3) Terrestrial animals require fresh water for transportation of minerals and for getting rid of waste from their body.
(4) Plants require water for photosynthesis.
Q2. What is the major source of fresh water in the city/town/ village where you live?
Ans. The major sources of water are:
(a) Water in the form of snow, ice-covered mountains.
(b) Underground water well.
(c) Surface water like in lakes, rivers, ponds.
(d) Rainfall.
Short Answer Type Questions
1. Write down the composition of the air.
Answer Air is a mixture of 79% nitrogen, 20% oxygen, 1% carbon dioxide, water vapors, and some other gases. Air also contains dust particles.
2. How does oxygen and carbon dioxide remain nearly constant in the atmosphere?
Answer Oxygen and carbon dioxide remain nearly constant in the atmosphere by the processes of photosynthesis (in plants) and respiration (in animals), respectively. This released oxygen is consumed by animals by the process of respiration, in which they release carbon dioxide.
3. How does the average temperature of Earth remain fairly steady?
Answer The average temperature of the Earth is maintained fairly steady by the atmosphere. It prevents a sudden increase in temperature during the daytime and slows down the escape of heat into the outer space at night. It also acts as a blanket covering the Earth