HBSE 9th Class Science Solutions Chapter 14 Natural Resources

Haryana State Board HBSE 9th Class Science Solutions Chapter 14 Natural Resources Textbook Exercise Questions and Answers.

Haryana Board 9th Class Science Solutions Chapter 14 Natural Resources

HBSE 9th Class Science Natural Resources Intext Questions and Answers

Questions from Sub-section 14.1

Question 1.
How is our atmosphere different from the atmospheres on Venus and Mars?
Answer:
The components of life air (breathe of life – oxygen) are present in our atmosphere while this lacks on Venus and Mars.

Question 2.
How does the atmosphere act as a blanket?
Answer:
Air present in the atmosphere is a bad conductor of heat which keeps the average temperature of the atmosphere fairly steady during day-night and even during the course of the whole year, such that a blanket prevents the heat to go out, just like that atmosphere prevents the heat of earth surface to go out and also does not let the temperature to be increased, therefore, the atmosphere acts as a blanket.

Question 3.
What causes winds?
Answer:
With uneven movements, the warming of the atmosphere of the earth creates somewhere low-pressure area and somewhere high-pressure area. The difference of this pressure creates airflow which is called breeze or wind.

Question 4.
How are clouds formed?
Answer:
Water vapours in the atmosphere when a pass from the cold areas then water vapours are condensed in the form of droplets. These droplets grow bigger and form the shape of clouds.

Question 5.
List any three human activities that you think would lead to air pollution.
Answer:
Following are the human activities which cause air pollution :
(1) Burning of fossil fuels produces pollutants, which pollute the air after mixing with it.
(2) Smoke from vehicles also pollutes the air.
(3) Gases from the industries/factories established by man also pollute the air after mixing with it.

Questions from Sub-section 14.2

Question 1.
Why do organisms need water?
Answer:
Water is the fundamental need of all living organisms. Every organism’s body contains 75% amount of water. In organisms, all biogeochemical reactions take place with water. Water medium is compulsory for all cellular reactions. Transportation of the substances in the bodies of the organisms takes place in a water medium and excretion activities also take place by water. Terrestrial organisms require freshwater to survive. Water is a living place at a lot of organisms.

Question 2.
What is the major source of freshwater in the city/town/village where your live ?
Answer:
In villages, towns and cities sources of freshwater are underground water, ponds, lakes and rivers. After melting the snow, water is available in the rivers coming from the mountains. In ponds, lakes, etc., mostly we find rainwater.

Question 3.
Do you know of any activity which may be polluting this water source?
Answer:
Sewage waste is mostly dumped into water resources (rivers, canals, lakes) which causes water pollution. Sewage excreta of metropolitan cities and towns situated on the banks of rivers is being dumped into rivers directly. Likewise, half burnt or unburnt dead bodies are thrown in the water of the Ganga by the habitats of the banks of Ganga due to which the water of Ganga is being polluted.

Questions from Sub-section 14.3

Question 1.
How is soil formed?
Answer:
Soil is formed by the breaking and grinding-rubbing of rocks. Soil is formed by the mixing of small pieces of rocks, fresh and decomposition of leaves, dead decayed remains of organisms and sand particles etc. The formation of topsoil of the earth takes a minimum 300 to 800 years. Soil formation is a continuous process.

Question 2.
What is soil erosion?
Answer:
Cutting or flowing away of the soil by any of the reasons is called soil erosion. Soil erosion may take place by various reasons, for example:
1. Flood: Flood is the main reason of soil erosion by which soil flows away from one place to another.
2. Fast Winds: The second main reason of soil erosion is the fast-blowing winds.
3. Deforestation: Deforestation is on high scale due to growing population and industrialisation by which soil erosion increases.
4. Uncontrolled and Overgrazing: Uncontrolled and overgrazing increases soil erosion.
5. Unscientific Techniques of Agriculture: Mostly farmers use to grow one variety of crops continuously in the fields by which fertility of soil decreases and soil erosion increases.
6. Deeper Cultivation of the Land: Soil erosion increases due to deeper cultivation of the land for farming.

Question 3.
What are the methods of preventing or reducing soil erosion?
Answer:
Following are the methods to prevent soil erosion:
1. By Growing Grass: Leaves and roots of grass retard the flow of water by which soil particles may not be flown by water.
2. By Levelling the Fields: By distributing the tapered land into small levelled pieces for agriculture, the flow of water is checked by which cutting of land is also prevented.
3. By Growing Trees: Roots of the trees bind the soil by which water cannot flow away the soil.
4. Better Techniques of Farming: In spite of ploughing in the sloping direction, if ploughing is being done in left-right sides of the field, then flow of water decreases, and erosion of soil is checked.
5. By Making Small Dams: Small dams constructed on slopes decrease the flow of fast-moving water
and soil erosion is stopped.
6. By Making Ladder-type Field: In hilly areas, farming should be done by making steps opposite to
slope.
7. By Using Manure: Use of manure in field increases the water retention efficiency of the soil by which soil erosion is checked.
8. By Fixing Air-protectors: Where the land is sandy and winds flow fast, there plants should be grown profusely around the field, i.e., fast winds may not flow away the soil particles.
9. By Making High Fences: Fences of the fields should be high because the water of field will not flow out and cutting of land is not possible.
10. By Growing Particular Crops : Soil erosion can be decreased by growing particular crops such as groundnut.

Questions from Sub-section 14.4,14.5

Question 1.
What are the different states in which water is found during the water cycle ?
Answer:
In water cycle, three states of water are found :
(i) Water in liquid state,
(ii) Water in vapour state and
(iii) Ice as solid state.

Vapours form clouds and these clouds bring rain on the earth and sometimes water of clouds freezes in ice, i.e., converts into hailstone. Ice on the peaks of the mountains is also water in solid state, which after melting comes in rivers and there by converting into vapours, mix with air.

Question 2.
Name two biologically important compounds that contain both oxygen and nitrogen.
Answer:
Nitrates and nitrites.

Question 3.
List any three human activities which would lead to an increase in the carbon dioxide content in air.
Answer:
Following are the reasons of human activities which cause an increase in the carbon dioxide content in air.
(i) By combustion of fuel.
(ii) By using petroleum products in vehicles.
(iii) CO₂is also released by respiration.

Question 4.
What is the greenhouse effect?
Answer:
The earth receives different types of radiation from the sun. The ozone layer in the atmosphere absorbs ultraviolet radiation and let go to other radiations, but radiations which come on the earth’s surface, some part of it in the form of infrared radiation reflected back. Molecules of CO₂ have the efficiency to absorb infrared radiations, hence carbon dioxide present in the atmosphere can absorb radiation, that reason atmosphere becomes warmer. The warming of the atmosphere in this way is called the greenhouse effect or glasshouse effect.

Question 5.
What are the two forms of oxygen found in the atmosphere?
Answer:
CO₂ (Oxygen) and O₃ (Ozone).

HBSE 9th Class Science Natural Resources Textbook Questions and Answers

Question 1.
Why is the atmosphere essential for life?
Answer:
Life is dependent only on the atmosphere because
(i) The atmosphere keeps the average temperature of the earth fairly steady.
(ii) Oxygen is available in the atmosphere in the form of life air.
(iii) Ozone layer of the atmosphere protects from the harmful ultraviolet radiation coming from the sun.
(iv) Atmosphere protects the earth from meteors, by which life is also protected.
(v) CO₂ gas which is used by green plants in photosynthesis is also found in the atmosphere.
(vi) Water in the atmosphere is found in the form of water vapours which is the foundation of life.
Hence, the atmosphere is essential for life.

Question 2.
Why is water essential for life?
Answer:
Water is the fundamental need of all living organisms. Every organism’s body contains 75% amount of water. In organisms, all biogeochemical reactions take place with water. Water medium is compulsory for all cellular reactions. Transportation of the substances in the bodies of the organisms takes place in a water medium and excretion activities also take place by the water. Terrestrial organisms require freshwater to survive. Water is a living place at a lot of organisms.

Question 3.
How are living organisms dependent on the soil ? Are organisms that live in water totally independent of soil as a resource?
Answer:
Soil is the base of life. All living organisms are dependent on soil directly or indirectly. Plants get nutrients from the soil in which main are water and minerals and all animals are dependent on plants. Animals get food and oxygen to respire from plants. Life of living organisms is not possible without plants and plants cannot survive without soil. Aquatic animals are also dependent on soil because they fulfil their requirements from plants.

Question 4.
You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather?
Answer:
Yes, we are able to predict the weather. By collecting the data through artificial satellites established in earth orbit, it is very easy to predict the forthcoming weather. After each half an hour reports and photographs are collected by INSAT-IB. Through these photographs, prediction is relayed which prove to be very useful.

Question 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:
Yes, isolating these activities to specific and limited areas would help in reducing pollution, e.g.,
(i) Air pollution will decrease by running the vehicles based on solar system batteries rather then fossil fue/ petroleum.
(ii) These will be a check on pollution if cooking of food, heating of water, etc. are done by the use of solar energy in place of coal, L.P.G., etc. fuels in houses.
(iii) These will be a check on soil pollution by using compost manure in the agricultural field rather than chemical fertilizers.
(iv) The water pollution will be decreased by using useful substances in the treatment plants inspite of throwing the industrial waste directly in the water bodies.

Question 6.
Write a note on how forests influence the quality of our air, soil and water resources.
Answer:
Forests are the main components in environmental balance. Forests equalize the formation (78% nitrogen, 21% oxygen) of air. This balance is disturbed by deforestation. Temperature increases with the increase of C02 and the content of condensed particles in air while the air becomes, dust free, pure and cool by the deep forestation. Forest decreases pollution. Forests help in maintaining the quality of soil by increasing its fertility and also preventing soil erosion. By deforestation land becomes barren. The temperature of the environment increases. Rains are excess by excess forestation. Water level increases in water bodies and makes the availability of useful fresh water in large quantities. Therefore, forests are helpful in improving the quality of air, soil and water resources.