NCERT Solutions for Class 9 Science Chapter 14 Natural Resources
In Class 9 Science Chapter 14 – Natural Resources, we study how air, water, soil, and forests maintain balance in nature and support living organisms. This chapter also explains important concepts like the atmosphere’s role, the water cycle, biogeochemical cycles, soil formation, pollution, and conservation of resources.
In this article, “NCERT Solutions for Class 9 Science Chapter 14 Natural Resources”, you will find easy-to-understand NCERT Solutions for Class 9 Science Chapter 14 Natural Resources to help you prepare well for your exams.
NCERT Textbook Solution for Class 9 — Page No: 193
1. How is our atmosphere different from the atmospheres on Venus and Mars?
Answer:
The Earth’s atmosphere is made up of a balanced mixture of gases such as nitrogen (78%), oxygen (21%), and small amounts of carbon dioxide (0.03%), water vapour, and other gases. This balance of gases makes life possible on Earth.
On the other hand, the atmospheres of Venus and Mars are very different. They are mostly made up of carbon dioxide. This carbon dioxide constitutes up to 95-97% of the atmosphere on Venus and Mars. Because of such high carbon dioxide levels and the lack of oxygen, these planets cannot support life as Earth does.
2. How does the atmosphere act as a blanket?
Answer
The atmosphere acts as a blanket by performing the following functions:
- It regulates temperature. The air in our atmosphere is a bad conductor of heat. This means it helps keep the Earth’s average temperature stable throughout the day and year.
- It prevents extreme heat and cold. During the day, the atmosphere prevents the sun’s heat and the sudden increase in temperature. At night, it slows down the escape of heat into outer space.
3. What causes winds?
Answer
Winds are mainly caused by the uneven heating of the Earth’s surface. When air gets heated, it becomes lighter and rises upward, creating a region of low pressure. Cooler air from a high-pressure area then moves in to fill this space. This movement of air from high pressure to low pressure causes winds.
4. How are clouds formed?
Answer
When water bodies are heated during the day, a large amount of water evaporates and goes into the air. Water vapour also enters the air through plants and other biological activities. This hot air rises up carrying the water vapour with it
As the air rises, it expands and cools. This cooling makes the water vapour condense into tiny droplets. Dust and other small particles in the air help these droplets to form. Slowly, the droplets join together and become bigger and heavier. When large numbers of these droplets gather together, they become visible as clouds. When they are too heavy to stay in the air, they fall to the ground as rain.
5. List any three human activities that you think would lead to air pollution.
Answer
Three human activities that cause air pollution are:
- Burning of fossil fuels like coal, petrol, and diesel.
- Deforestation and burning of wood or crop residues.
- Industrial emissions and construction activities.
NCERT Textbook Solution for Class 9 — Page No: 194
1. Why do organisms need water?
Answer
Organisms need water because:
- All cellular processes take place in a water medium.
- Most chemical reactions in the body occur when substances are dissolved in water.
- Water helps in transporting food, minerals, and waste materials.
- In plants, water is needed for photosynthesis.
- In animals, water supports digestion, absorption of nutrients, and removal of wastes.
- It helps regulate body temperature.
2. What is the major source of fresh water in the city/town/village where you live?
Answer
The major sources of fresh water in cities, towns, or villages are:
Rainfall
Underground water
Rivers, ponds, and lakes.
Snow.
3. Do you know of any activity which may be polluting this water source?
Answer
Some activities that may pollute fresh water sources are:
- Dumping household sewage and waste directly into rivers, ponds, or lakes.
- Use of chemical fertilisers and pesticides in farming that get washed into water bodies.
- Throwing plastic, garbage, and other solid waste into ponds, rivers, or lakes.
- Discharge of harmful chemicals and waste from factories into water bodies.
- Release of hot water from industries which affects aquatic life.
NCERT Textbook Solution for Class 9 — Page 196
1. How is soil formed?
Answer
Soil is formed when rocks at or near the surface of the Earth are broken down into tiny particles slowly over thousands of years. This process happens due to physical, chemical, and biological factors. Factors that help in the formation of soil are as follows:
- The Sun: The sun’s heat causes rocks to expand during the day and contract at night. This uneven expansion and contraction forms cracks, which eventually break the rocks into smaller pieces.
- Water: Water enters these cracks of rocks. When it freezes, it expands and widens the cracks. Flowing water also rubs and wears away rocks, breaking them into small particles and carrying the broken particles to other places where they get deposited as soil.
- Wind: Similar to flowing water, strong winds can also erode rocks by rubbing and carries sand from one place to the other.
- Living Organisms: Lichens grow on rocks and release substances that turn the rock surface into thin soil. Then moss and small plants grow on this surface, which break the rock further. Roots of big trees also enter rock cracks, and as they grow, they make the cracks wider.
2. What is soil erosion?
Answer
Soil erosion is the removal of the top layer of soil by wind or running water. This topsoil is rich in humus and nutrients, so when it gets washed or blown away, the fertility of the land decreases. If soil erosion continues for a long time, the rocks underneath may get exposed, and plants will not be able to grow properly.
3. What are the methods of preventing or reducing soil erosion?
Answer
Soil erosion can be reduced or prevented by the following methods:
- Planting vegetation: The roots of plants are crucial in preventing soil erosion. A topsoil layer that is bare of vegetation is easily removed, especially in hilly or mountainous regions. Planting trees or other vegetative covers helps to hold the soil in place and also helps water percolate into deeper layers of the ground.
- Avoiding deforestation: The large-scale deforestation happening around the world not only destroys biodiversity but also leads to soil erosion. By preventing deforestation, we can help preserve the natural vegetative cover that holds the soil.
NCERT Textbook Solution for Class 9 — Page No: 201
1. What are the different states in which water is found during the water cycle?
Answer
During the water cycle, water is found in three different states:
- Liquid state – in rivers, lakes, ponds, and underground water.
- Gaseous state – as water vapour in the atmosphere after evaporation.
- Solid state – as ice and snow in glaciers, polar caps, and snow-covered mountains.
2. Name two biologically important compounds that contain both oxygen and nitrogen.
Answer
Two biologically important compounds that contain both oxygen and nitrogen are:
Proteins and
Nucleic acids (DNA and RNA)
3. List any three human activities which would lead to an increase in the carbon dioxide content of air.
Answer
Three human activities that increase the carbon dioxide content of air are:
- Combustion of fuels: Burning fuels for purposes like heating, cooking, transportation and industrial processes releases carbon dioxide into the atmosphere.
- Large-scale burning of fossil fuels: The use of foss il fuels on a very large scale, especially since the Industrial Revolution, has doubled the percentage of carbon dioxide in the atmosphere.
- Respiration: Respiration is a biological process in which living organisms use oxygen to break down glucose and release carbon dioxide into the air.
- Deforestation: Trees absorb carbon dioxide and convert it into food like glucose and starch through photosynthesis. If too many trees are cut down carelessly, the carbon dioxide level in the environment increases.
Answer
Some gases, like carbon dioxide, methane, nitrous oxide trap heat and prevent it from escaping into space. As a result, the average temperature of the Earth is increasing worldwide. This warming of the atmosphere due to trapped heat is called the greenhouse effect.
5. What are the two forms of oxygen found in the atmosphere?
Answer
The two forms of oxygen found in the atmosphere are:
- Diatomic oxygen (O₂): The normal form of oxygen that we breathe.
- Triatomic oxygen (O₃) (Ozone): This is a molecule containing three atoms of oxygen, written as O₃. It is known as ozone. It is found in the upper atmosphere that protects us from harmful ultraviolet rays of the Sun.
Exercises Page No: 201
1. Why is the atmosphere essential for life?
Answer
Atmosphere is essential for life because of the following masons :
- The atmosphere acts like a blanket, keeping the Earth’s average temperature stable.
- It prevents a sudden increase in temperature during the day and slows down the escape of heat at night.
- The ozone layer in the atmosphere protects living beings from harmful ultraviolet (UV) rays of the Sun.
- It contains gases like oxygen for breathing, carbon dioxide for photosynthesis, and nitrogen for making proteins.
2. Why is water essential for life?
Answer
Water is essential for life because of the following reasons:
- All cellular processes take place in a water medium.
- All the biological reactions that take place within our body and within the cells occur in water medium.
- Water helps transport substances from one part of the body to another in a dissolved form.
- Water helps in the digestion of food and absorption of nutrients in the blood.
- It also helps in maintaining body temperature.
- Organisms that live on land need fresh water because their bodies can’t tolerate or get rid of the high amounts of dissolved salts found in saline water. Therefore, animals and plants must have easy access to water sources to survive on land.
3. How are living organisms dependent on the soil? Are organisms that live in water totally independent of soil as a resource?
Answer
All living organisms on the earth are dependent on soil directly or indirectly, for their survival in the following ways :
- Soil provides essential minerals and nutrients needed for plant growth.
- So, plants get their nutrients from the soil, and animals depend on plants, so the entire food chain on land is connected to the soil.
- The soil also serves as a habitat for organisms like earthworms, bacteria, and other microorganisms that play crucial roles in breaking down dead matter and recycling nutrients back into the ecosystem.
- Soil also acts as a natural water reservoir.
Are organisms that live in water totally independent of soil?
No, organisms that live in water are not totally independent of soil. Aquatic organisms depend on aquatic plants for food and shelter. These plants need minerals to survive. As water flows through rocks containing soluble minerals, some of them get dissolved in the water. Thus rivers carry many nutrients from the land to the sea, and these are used by the marine organisms. So, aquatic organisms depend on nutrients that ultimately come from soil through the water cycle.
4. You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather?
Answer
Meteorologists collect and study data about temperature, rainfall, wind speed, humidity, and air pressure. Instruments like thermometers, rain gauges, and anemometers are used for this. Nowadays, satellites and remote sensing devices also give detailed data about clouds and atmospheric changes. All this information is analysed, and then weather reports are prepared, which are shared through newspapers, radio, and television. Hence, we are able to forecast the weather, on the basis of the data collected by the meteorologists.
5. We know that many human activities lead to increasing levels of pollution of the air, water-bodies and soil. Do you think that isolating these activities to specific and limited areas would help in reducing pollution?
Answer:
Isolating polluting activities to limited areas may reduce their harmful effects in some places, but it will not solve the overall problem of pollution. Air, water, and soil are interconnected and spread beyond boundaries. For example, polluted air can travel long distances with wind, and polluted water can flow into rivers and seas. Therefore, the only effective solution is to control and reduce pollution at the source by using cleaner technologies, proper waste treatment, and sustainable practices.
6. Write a note on how forests influence the quality of our air, soil and water resources.
Answer
Forests influence the quality of our air, soil, and water resources in various ways. Some of them are:
Air:
- Forests act as the “lungs of nature.”
- Forests help in increasing the oxygen level in the air by absorbing carbon dioxide during photosynthesis.
- Some of the trees in forests has the ability to absorb harmful gases present in the atmosphere and dust from the atmosphere.
- Transpiration from leaves adds moisture to the atmosphere, which keeps the temperature cool and also helps in the formation of clouds.
Soil:
- Plants in forests hold the soil firmly, thereby preventing soil erosion.
- Forests also improve soil fertility, as the decayed leaves and plant matter add organic nutrients to the soil.
Water:
- Forests help in maintaining the water cycle. Through transpiration, trees release water vapour that leads to cloud formation and rainfall. This rainfall recharges rivers, ponds, and underground water levels.
NCERT Solutions for Class 9 Science Chapter 1 Matter In Our Surroundings
NCERT Solutions for Class 9 Science Chapter 2 Is Matter Around Us Pure?
NCERT Solutions for Class 9 Science Chapter 3 Atoms And Molecules
NCERT Solutions for Class 9 Science Chapter 4 Structure Of The Atom
NCERT Solutions for Class 9 Science Chapter 5 The Fundamental Unit Of Life
NCERT Solutions for Class 9 Science Chapter 6 Tissues
NCERT Solutions for Class 9 Science Diversity In Living Organism
NCERT Solutions for Class 9 Science Chapter 8 Motion
NCERT Solutions for Class 9 Science Chapter 9 Force And Laws Of Motion
NCERT Solutions for Class 9 Science Chapter 10 Gravitation
NCERT Solutions for Class 9 Science Chapter 11 Work And Energy
NCERT Solutions for Class 9 Science Chapter 12 Sound
NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall ill
NCERT Solutions for Class 9 Science Chapter 14 Natural Resources
NCERT Solutions for Class 9 Science Chapter 15 Improvement In Food Resources