MP Board Class 9th Science Solutions Chapter 14 Natural Resources

Natural Resources Intext Questions

Natural Resources Intext Questions Page No. 193

Question 1.
How is our atmosphere different from the atmospheres on Venus and Mars?
Answer:
Earth’s atmosphere has mixture of nitrogen (79%), oxygen (20%), and a small fraction of carbon dioxide, water vapours and other gases which makes the existence of life possible on Earth while the atmospheres on Venus and Mars mainly has carbon dioxide. Approximately, 95% to 97% is carbon dioxide is present on these planets which do not support existence of life.

Question 2.
How does the atmosphere act as a blanket?
Answer:
Atmosphere is a mixture of various gases along with vapour and submerged particles. It surrounds the earth and separates it from outer space. As a blanket stop interaction between body covered inside and atmosphere outside, in similar way atmosphere stops interaction between earth and space.
The most important isolations done by atmosphere are:

It keeps the average temperature of the Earth fairly constant during day time and even during the course of whole year.
It prevents a sudden increase in the temperature during day time.
It slows down the escape of heat from the surface of the Earth into outer space during night time.

Question 3.
What causes winds?
Answer:
Atmospheric pressure and temperature difference generates wind. As earth surface is not similar everywhere even at some places it is occupied by huge water bodies, lava emitting volcanoes, moist forest etc., a difference in temperature and pressure arises and to maintain equilibrium wave of pressure moves which we feel or notice as wind.

Question 4.
How are clouds formed?
Answer:
During day time, a large amount of water evaporates from various water bodies and of earth surface and through biological activities such as transpiration and respiration and mix up into the air. This causes the air in the atmosphere to heat up and since air is a bad conductor of heat, when this heated air rises, it expands and cools, which results in the condensation and formation of water droplets. The presence of dust and other suspended particles in air also facilitates cloud formation. The gathering of water droplets leads to the formation of clouds.

Question 5.
List any three human activities that you think would lead to air pollution.
Answer:
Three human activities leading to air pollution are:

Smoke from industrial and manufacturing activities etc.
Burning of fossil fuels for household and commercial purpose.
Spreading farming chemicals such as crop dusting, insect / pest killers, fertilizer dust etc.

Natural Resources Intext Questions Page No. 194

Question 1.
Why do organisms need water?
Answer:
Water is the major component of living organism some of the living organism has up to 90% of water of their body weight. Water is a wonderful liquid, it helps in performing most of the functions of our body like digestion, cell sap and oilier content formation, transportation of substance from one place to another inside the body etc.

Question 2.
What is the major source of fresh water in the city’town/ village where you live?
Answer:
The major source of fresh water near me is river.

Question 3.
Do you know of any activity which may be polluting this water source?
Answer:
Dumps from industrial activities, household works for various purpose in the fresh water sources are main activities which causes pollution. Air pollution which generates acid rain and spread submerged dust is also responsible for polluting water resources.

Natural Resources Intext Questions Page No. 196

Question 1.
How is soil formed?
Answer:
The process of soil formation is termed ‘paedogenesis’. Soil is formed mainly by the weathering of rocks through various physical chemical and biological processes with the help of various factors such as the sun, water, wind, and living organisms. It is made up of mineral particles, organic materials, air, water and living organisms. During day time, the rocks are heated up by solar rays. This causes the rocks to expand. During night time, these rocks cool down and contracts. It causes weathering of rock and formation of soil.

Water: It helps in breaking of rocks in two ways:
- It goes into the cracks and crevices formed in the rocks. When this water freezes, its volume increases. As a result, the size of the cracks also increases. This helps in the weathering of rocks.
- Water moving at fast speed carries big and small particles of rock downstream. These rocks rub against each other, resulting in breaking down of rocks. These smaller particles are carried away by running water and deposited down its path.
Wind: Strong winds carry away rocks, which causes rubbing of rocks. This results in the breaking down of rocks into smaller and smaller particles.
Living Organism: Some living organisms like lichens help in the formation of soil. Lichens grow on rock surfaces and converts them into powdery form and make soil layer. In the same way, the plants like moss also helps in the making of fine soil particles.

Question 2.
What is soil erosion?
Answer:
The blowing away or washing away of land surface by wind or water is known as soil erosion.

Question 3.
What are the methods of preventing or reducing soil erosion?
Answer:
The methods of preventing or reducing soil erosion are:

Plantation of tress and plants.
Prevention of deforestation.
Prevent excessive grazing.

Natural Resources Intext Questions Page No. 201

Question 1.
What are the different states in which water is found during the water cycle?
Answer:
Water is found in three different states during the water cycle:

Solid (snow, ice).
Liquid water (ground water, river water, etc.)
Gaseous state (water vapours).

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

Amino acids.
Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA).

Question 3.
List any three human activities which would lead to an increase in the carbon dioxide content of air.
Answer:
Three Human activities are:

Burning of fuels in various processes like heating, cooking, transportation and industry.
Human induced forest fires.
The process of deforestation includes the cutting down of trees. This decreases the uptake of carbon dioxide for photosynthesis. Eventually, the content of carbon dioxide increases.

Question 4.
What is the greenhouse effect?
Answer:
Some gases like carbon dioxide, methane, nitrous oxide prevent the escape of heat from the Earth’s surface by trapping it. This increases the average temperature of the Earth. This is called the green house effect.

Question 5.
What are the two forms of oxygen found in the atmosphere?
Answer:
The two forms of oxygen found in the atmosphere are:

Diatomic molecular form with chemical formula O₂.
Triatomic molecular form with chemical formula O₃ known as ozone.

Natural Resources NCERT Textbook Exercise

Question 1.
Why is the atmosphere essential for life?
Answer:
The atmosphere is essential for life because it maintains an appropriate climate for the sustenance of life by carrying out the following activities:

Atmosphere keeps the average temperature of the earth fairly constant during day time.
It prevents a sudden increase in temperature during day time.
It also slows down the escape of heat from the surface of the earth into outer space during night time.

Question 2.
Why is water essential for life?
Answer:
Water is essential for life because of the following reasons:

Most biological reactions occur when substances are dissolved in water. Thus, all cellular processes need water as a medium to take place.
Transportation of biological substances needs water as a medium.

Question 3.
How are living organisms dependent on the soil?
Or
Are organisms that live in water totally independent of soil as a resource?
Answer:
Almost all living organisms are dependent on soil. Some depends directly, while some depends indirectly. Plants need soil for getting support as well as nutrients to prepare their food. On the other hand, organisms depend on plants for food and other substances that are essential for life. Herbivores depend directly upon plants and carnivores depend upon animals, which in turn depend upon plants for food. This makes them depend on soil indirectly.

Organisms that live in water are not totally independent of soil as a resource. These organisms depend on aquatic plants for food and other substances. These aquatic plants in turn require minerals for their sustenance. These minerals are carried to water bodies from soil by rivers, rain water etc. Without the supply of minerals from the soil to the water bodies, it is impossible to imagine aquatic life.

Question 4.
You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather?
Answer:
The meteorological department of the government collects data on the elements of weather such as maximum and minimum temperatures, maximum and minimum humidity, rainfall, wind speed etc. They are able to study these elements using various instruments. The maximum and minimum temperature of a day is measured by a thermometer known as the maximum – minimum thermometer. Rain fall is measured by an instrument known as the rain gauge. Wind speed is measured by anemometers. There are various instruments used to measure humidity.

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 human activities to specific areas would help in reducing levels of pollution. For example, setting up of industries in isolated regions will control pollution to some extent. The pollution caused by these industries will not contaminate water resources, agriculture land, fertile land, etc.

Question 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:

Forests balance the percentages of carbon dioxide and oxygen in the atmosphere. The increasing amount of carbon dioxide caused by human activities is balanced by a larger intake of carbon dioxide by plants during
the process of photosynthesis. Simultaneously, a large amount of oxygen is released.
Forests prevent soil erosion. Roots of plants bind the soil tightly in a way that the surface of the soil cannot be eroded away by wind, water etc.
Forests help in the replenishment of water resources. During the process of transpiration, a huge amount of water vapour goes into the air and condenses to form clouds. These clouds cause rainfall that recharge water bodies.

Natural Resources Additional Questions

Natural Resources Multiple Choice Questions

Question 1.
The atmosphere of the earth is heated by radiations which are mainly ___________ .
(a) radiated by the sun
(b) re – radiated by land
(c) re – radiated by water
(d) re – radiated by land and water.
Answer:
(d) re – radiated by land and water.

Question 2.
If there were no atmosphere around the earth, the temperature of the earth will ___________ .
(a) increase.
(b) go on decreasing.
(c) increase during day and decrease during night.
(d) be unaffected.
Answer:
(c) increase during day and decrease during night.

Question 3.
What would happen, if all the oxygen present in the environment is converted to ozone?
(a) We will be protected more.
(b) It will become poisonous and kill living forms.
(c) Ozone is not stable, hence it will be toxic.
(d) It will help harmful sun radiations to reach earth and damage many life forms.
Answer:
(b) It will become poisonous and kill living forms.

Question 4.
One of the following factors does not lead to soil formation in nature ___________ .
(a) the sun
(b) water
(c) wind
(d) polythene bags.
Answer:
(d) polythene bags.

Question 5.
The two forms of oxygen found in the atmosphere are ___________ .
(a) water and ozone
(b) water and oxygen
(c) ozone and oxygen
(d) water and carbon – dioxide.
Answer:
(c) ozone and oxygen

Question 6.
The process of nitrogen – fixation by bacteria does not take place in the presence of ___________ .
(a) molecular form of hydrogen
(b) elemental form of oxygen
(c) water
(d) elemental form of nitrogen.
Answer:
(b) elemental form of oxygen

Question 7.
Rainfall patterns depend on ___________ .
(a) the underground water table.
(b) the number of water bodies in an area.
(c) the density pattern of human population in an area.
(d) the prevailing season in an area.
Answer:
(b) the number of water bodies in an area.

Question 8.
Among the given options, which one is not correct for the use of large amount of fertilisers and pesticides?
(a) They are eco – friendly.
(,b) They turn the fields barren after sometime.
(c) They adversely affect the useful component from the soil.
(d) They destroy the soil fertility.
Answer:
(a) They are eco – friendly.

Question 9.
The nitrogen molecules present in air can be converted into nitrates and nitrites by ___________ .
(a) a biological process of nitrogen fixing bacteria present in soil.
(b) a biological process of carbon fixing factor present in soil.
(c) any of the industries manufacturing nitrogenous compounds.
(d) the plants used as cereal crops in field.
Answer:
(a) a biological process of nitrogen fixing bacteria present in soil.

Question 10.
One of the following processes is not a step involved in the water – cycle operating in nature ___________ .
(a) evaporation
(b) transpiration
(c) precipitation
(d) photosynthesis.
Answer:
(d) photosynthesis.

Question 11.
The term “water – pollution” can be defined in several ways. Which of the following statements does not give the correct definition?
(a) The addition of undesirable substances to water – bodies.
(b) The removal of desirable substances from water – bodies.
(c) A change in pressure of the water bodies.
(d) A change in temperature of the water bodies.
Answer:
(c) A change in pressure of the water bodies.

Question 12.
Which of the following is not a green house gas?
(a) Methane
(b) Carbon dioxide
(c) Carbon monoxide
(d) Ammonia.
Answer:
(d) Ammonia.

Question 13.
Which step is not involved in the carbon – cycle?
(a) Photosynthesis
(b) Transpiration
(c) Respiration
(d) Burning of fossil fuels.
Answer:
(b) Transpiration

Question 14.
‘Ozone – hole’ means
(a) a large sized hole in the ozone layer.
(b) thinning of the ozone layer.
(c) small holes scattered in the ozone layer.
(d) thickening of ozone in the ozone layer.
Answer:
(b) thinning of the ozone layer.

Question 15.
Ozone – layer is getting depleted because of ___________ .
(a) excessive use of automobiles.
(b) excessive formation of industrial units.
(c) excessive use of man – made compounds containing both fluorine and chlorine.
(d) excessive deforestation.
Answer:
(c) excessive use of man – made compounds containing both fluorine and chlorine.

Question 16.
Which of the following is a recently originated problem of environment?
(a) Ozone layer depletion.
(b) Green house effect.
(c) Global warming.
(d) All of the above.
Answer:
(d) All of the above.

Question 17.
When we breathe in air, nitrogen also goes inside along with oxygen. What is the fete of this nitrogen?
(a) It moves along with oxygen into the cells.
(b) It comes out with the CO₂ during exhalation.
(c) It is absorbed only by the nasal cells.
(d) Nitrogen concentration is already more in the cells so it is not at all absorbed.
Answer:
(b) It comes out with the CO₂ during exhalation.

Question 18.
Top – soil contains the following ___________ .
(a) Humus and living organisms only.
(b) Humus and soil particles only.
(c) Humus, living organisms and plants.
(d) Humus, living organisms and soil particles.
Answer:
(d) Humus, living organisms and soil particles.

Question 19.
Choose the correct sequences ___________ .
(a) CO₂ in atmosphere → decomposers → organic carbon in animals → organic carbon in plants.
(b) CO₂ in atmosphere → organic carbon in plants → organic carbon in animals → inorganic carbon in soil.
(c) Inorganic carbonates in water → organic carbon in plants → organic carbon in animals → scavengers.
(d) Organic carbon in animals → decomposers → CO₂ in atmosphere → organic carbon in plants.
Answer:
(b) CO₂ in atmosphere → organic carbon in plants → organic carbon in animals → inorganic carbon in soil.

Question 20.
Major source of mineral in soil is the ___________ .
(a) parent rock from which soil is formed.
(b) plants.
(c) animals
(d) bacteria.
Answer:
(a) parent rock from which soil is formed.

Natural Resources Very Short Answer Type Questions

Question 1.
Name the factor responsible for rainfall patterns in India.
Answer:
North – East or South – West Monsoons.

Question 2.
Name any two organisms. Which play important role in nitrogen – fixation.
Answer:
Rhizobium and Nitrosomonas.

Question 3.
State the process and the form by which carbon enters in the living system.
Answer:
Respiration.

Question 4.
Write any one difference between oxygen and ozone.
Answer:
Oxygen is diatomic (O₂) whereas ozone is triatomic (O₃).

Question 5.
What is the temperature range on the surface of moon?
Answer:
-190°C to 110°C.

Natural Resources Short Answer Type Questions

Question 1.
Rivers from land, add minerals to sea water. Discuss, how?
Answer:
Water is wonderful solvent. As water flows over the rocks which containing soluble minerals and these mineral get dissolved in the water. Thus, Rivers from land, add minerals to sea water.

Question 2.
How can we prevent the loss of top soil?
Answer:
Loss of top soil can be prevented by stopping the falling of trees and excessive grazing by animals, growing more the vegetation cover.

Question 3.
How is the life of organisms living in water affected when water gets polluted?
Answer:
When water gets polluted, oxygen does not dissolves in water properly, which effects the aquatic organisms adversely. Also, due to undesirable chemicals and waste discharge from factories and households cause diseases to the aquatic organisms.

Question 4.
During summer, if you go near the lake, you feel relief from the heat, why?
Answer:
Due to evaporation of water, air nearby water bodies become cooler.

Question 5.
In coastal area, wind current moves from the sea towards the land during day; but during night it moves from land to the sea. Discuss the reason.
Answer:
Air above the land gets heated quickly during day and starts rising. This creates a region of low pressure as a result air over sea rushes into this area of low pressure. This movement of air from one region to the other creates winds. During night, as water cools down slowly, the air above water is warmer than the air on land. So, air moves from land to sea creating winds.

Question 6.
Following are a few organisms: (a) lichen (b) mosses (c) mango tree (d) cactus.
Which among the above can grow on stones; and also help in formation of soil? Write the mode of their action for making soil.
Answer:
Lichens and Mosses: (a) and (b).
Lichens and mosses release materials which break down the stones causes formation of soil.

Question 7.
Soil formation is done by both abiotic and biotic factors. List the names of these factors by classifying them as abiotic and biotic?
Answer:

Sun, water and wind are abiotic factors that forms soil.
Lichens, mosses and trees are biotic factors which form soil.

Question 8.
All the living organisms are basically made up of C, N, S, P, H and O. How do they enter the living forms? Discuss.
Answer:
In 1952, Stanley Miller along with Harold C. Urey designed an experiment to see how complex organic molecules might have formed under the conditions of early Earth. From long experimental method he developed organic matter from non living things. And, concluded that on specific environmental conditions non living things grow up to living form.

Question 9.
Why does the percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere?
Answer:
The percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere because cycling of these gases maintains consistency.

Question 10.
Why does moon have very cold and very hot temperature variations e.g., from -190°C to 110°C even though it is at the same distance from the sun as the earth is?
Answer:
No atmosphere exists on the moon thus, moon have very cold and very hot temperature variations e.g., from -190°C to 110°C even though it is at the same distance from the sun as the earth.

Question 11.
Why do people love to fly kites near the seashore?
Answer:
People love to fly kites near the seashore because air gets heated quickly during day and creates wind, which helps them to fly kites easily.

Question 12.
Why does Mathura refinery pose problems to the Taj Mahal?
Answer:
Polluted environment of Mathura due to refinery and other infrastructural facilities, industries etc. release toxic gases (like oxides of sulphur) which causes acid rain and corrode the marbles of Taj Mahal.

Question 13.
Why does water need conservation even though large oceans surround the land masses?
Answer:
Marine water is not useful for human and plant life directly. Hence fresh water need conservation. Uneven distribution of limited fresh water resources need conservation to ft ever rising demands.

Question 14.
There is mass mortality of fishes in a pond. What ma) the reasons?
Answer:

Thermal pollution
Addition of poisonous (mercury) compounds in water
Due to blockage of gills with any pollutant.

Natural Resources Long Answer Type Questions

Question 1.
How do fossil fuels cause air pollution?
Answer:
Most of air pollution of our environment is caused by the burning of fossil fuels, such as coal, oil natural gas and gasoline to produce electricity and power out vehicles. Carbon dioxide (CO₂) is a good indicator of how much fossil fuel is burnt and how much of other pollutants are emitted as a result. When fossil fuels are burnt, they release primarily nitrogen oxides into the atmosphere, which leads to the formation of smog and simultaneously acid rain.

The most common nitrogen – related compounds emitted into the air by human activities are collectively referred to as nitrogen oxides. Ammonia is also a harmful nitrogen compound emitted to the air, agricultural activities also contribute in air pollution but fossil fuels are most common reason for its increase day by day.

Question 2.
What are the causes of water pollution? Discuss how you can contribute in reducing water pollution.
Answer:
Domestic and industrial waste dump to water – bodies are main reason of water pollution. Industries produce huge amount of waste which contains toxic chemicals and pollutants which can cause air pollution and damage us and our environment. They contain pollutants such as lead, mercury, sulphur, asbestos, nitrates and many harmful chemicals.

Prevention of water pollution:
Stop dumping waste in water – bodies is the only way to get clear water resources. Do not throw chemicals, oils, paints and medicines down the sink drain or the toilet. If you use chemicals and pesticides for your gardens and farms, be mindful not to overuse pesticides and fertilizers. This will reduce run offs of the chemical into nearby water sources.

Natural Resources Higher Order Thinking Skills (HOTS)

Question 1.
If decomposers are removed completely from the Earth, what will be the result? Give reasons.
Answer:
Decomposers are the organisms that feed on dead and decaying matter present on the Earth. These organisms decompose the dead plants and animals returning the complex nutrients present in them in available form to the nature.

Question 2.
Why is nitrogen – fixing bacteria found only in the roots of leguminous plants?
Answer:
The roots of leguminous plants contains root nodules. These nodules provide shelter to nitrogen fixing bacteria like Rhizobium.

Natural Resources Value Based Questions

Question 1.
Manisha lived near industrial area in Delhi. During winters . she saw that the smoke has reduced the visibility in the area. Manisha requested the industries to fit in chimney the precipitators that would not release smoke particulates in air.

What is smog?
Name two disease caused due to air pollution.
What values are displayed by Manisha?

Answer:

When smoke is added to fog, smog is formed.
Air – pollution causes respiratory problem and allergies.
Manisha showed the value of self-awareness, and responsible behaviour.

Question 2.
Radha saw a child sleeping in a car parked with closed doors and glass rolled up in the open area on a sunny day near the market. She immediately raised an alarm and with the help of police, she got the window glass rolled down.

Why was it not safe to keep the doors with window glass rolled Up for a child inside the car?
Name two gases that can lead to above effect.
What values are exhibited by Radha?

Answer:

It was not safe for the child in the car with locked doors and window rolled up, the sunlight would result in the green house effect in the car. This would increase the temperature in the car and also result in the increase in CO₂ level which would lead to suffocation.
Carbon dioxide gas and methane gas can lead to green house effect.
Radha displayed the value of aware citizen and responsible behaviour.