NCERT Exemplar Solution Class 9 Science Chapter 14
NCERT Exemplar Solution Class 9 Science Chapter 14 Natural Resources all Questions Answer Solution. NCERT Exemplar Class 9 Science Chapter 14 Solution PDF.
NCERT Exemplar Solution Class 9 Science Chapter 14: Overview
NCERT Exemplar Solution Class 9 Science Chapter 14 |
|
Board |
NCERT |
Topic |
Exemplar Problem Solution |
Class |
9 |
Subject |
Science |
Chapter |
14 |
Chapter Name |
Natural Resources |
NCERT Exemplar Solution Class 9 Science Chapter 14 Natural Resources
Chapter14
Natural resources
Multiple Choice Questions
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 .
The Sunray falls on the earth are bounced back to the atmosphere which is captured by the atmosphere and thus the temperature over the earth is maintained.
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.
Atmosphere plays an important role in the maintaining the temperature of the earth. Layer of Atmosphere captures the sunrays which fall on the earth also it bounce back the harmful rays. But if the atmosphere and the Ozone is not there then sunray will directly come upon the earth during the day and it will Become so hot and at night the planet will be cooled down so much so there be decrease in temperature.
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.
Every living thing need oxygen which is O2 for one of the important function of our body which is breathing. But if all the oxygen converted into the ozone i.e O3 then it will be dangerous for humans. We will be killed by it.
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
Polythene bags are manmade thing which does not play the role in the formation of soil. These is the plastic waste after once used. While the other options sun, water and wind break the rocks and turns it to soil.
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
Ozone is O3 that is 3 molecules of oxygen together forms ozone compound. And oxygen is O2 that is 2 molecules of Oxygen together forms Oxygen gas.
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.
Oxygen is not the part of the nitrogen fixation it contains nitrogen from environment and water which is absorbed by the roots and water consist of hydrogen as well.
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.
The rainfall dependent upon the evaporation of the water in that area that larger the water bodies present in the area the large amount of evaporation will be there so the large amount clouded will form and large rainfall will be in that area.
8) Among the given options, which one is not correct for the use of large amount of fertilizers and pesticides?
a) They are eco-friendly
b) They turn the fields barren after some time
c) They adversely affect the useful component from the soil
d) They destroy the soil fertility
Answer:- a) They are eco friendly
Use of large amount of Fertilizers and pesticides is not at all eco friendly these are tremendously Harmful to the environment as they contain large quantity of chemicals.
9) A 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 a cereal crops in field
Answer:- a)A biological process of nitrogen fixing bacteria present in soil.
Some leguminous plants contains nodules in their roots which have Rhizobium bacteria. That bacteria can convert the atmospheric nitrogen into the nitres and nitrites by some chemical process which is further used by plants growth.
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
Photosynthesis is the process of formation of food of the plant. It is not involved in the water cycle.
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 from 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
The change in pressure in the water bodies is not due to the water pollution pressure can be changed by any external force or activity, but pollution of water is simply addition of harmful substances to the water bodies.
12) Which of the following is not a green house gas ?
a) Methane
b) Carbon dioxide
c) Carbon monoxide
d) Ammonia
Answer:-d) Ammonia
Green house gases includes carbon dioxide, methane, Chlorofluorocarbons, water vapours etc. These does not include Ammonia.
13) Which step is not involved in the carbon- cycle?
a) Photosynthesis
b) Transpiration
c) Respiration
d) Burning of fossil fuels
Answer:- b) Transpiration
Transpiration is the process in which trees or plants remove some amount of water through their stomata present on the tip of the leaves. These is not included in the carbon cycle.
14) Ozone – hole means
a) A large sized hole in the ozone layer
b) Thinning if the ozone layer
c) Small holes scattered in the ozone layer
d) Thickening of ozone in the ozone layer
Answer:- b) Thinning if the ozone layer.
The ozone layer is getting thinner and the process of formation of hole is started over there. These is due to the gases like Chlorofluorocarbons.
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.
Ozone layer deletion is the reducing of ozone layers thickness. There is formation of hole in the ozone layer which is due to the gases like fluorine, Chlorine or CFCs which is also known as Chlorofluorocarbons.
16) Which of the following is a recently originated problem if environment ?
a) Ozone layer depletion
b) Green house effect
c) Global warming
d) All of the above
Answer:- d) All of the above.
Ozone layer depletion, green house effect and global warming are the recently originated problem in the environment because as the population of the earth Increasing the use of many chemicals is Increasing which is also increasing the level of harmful gases in the environment this these all the problems are originating.
17) When we breathe in the air, nitrogen also goes inside along with oxygen. What is the fate 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.
Nitrogen is not useful for any function of our body thus it is expelled out from the body along with the carbon dioxide
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.
The dead and decaying living organisms and the humus is the major source of nutrients which is needed by plants. These all is present in the top layer of the soil.
19) Choose the correct sequences
a) CO2 in atmosphere → decomposer → 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 → decomposer → CO2 in atmosphere → organic carbon in plants
Answer:- b) CO2 in atmosphere → organic carbon in plants → organic carbon in animals→ inorganic carbon in soil.
These is the correct sequence. From the photosynthesis of the plants then it goes to the animals and then to the decomposition of the plant.
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
The parent rock form the top layer of soil which is full of nutrients these nutrients and minerals are important for the plants growth. Thus these is the major source of minerals.
21) Total earth’s surface covered by water is
a) 75%
b) 60%
c) 85%
d) 50%
Answer:- a)75%
Water covered 75% over the earth surface. 25 % is covered by land.
22) Biotic component of biosphere is not constituted by
a) Producers
b) Consumers
c) Decomposers
d) Air
Answer:- d) Air
Air is not biotic component because it is non – living thing which is abiotic.
23) An increase in carbon dioxide content in the atmosphere would not cause
a) More heat to be retained by the environment
b) Increase in photosynthesis in plants
c) Global warming
d) Abundance of desert plants
Answer:- d) Abundance of desert plants
Plants need carbon dioxide but in limited quantity increased Carbon dioxide is also harmful for the plants.
24) Oxygen is returned to the atmosphere mainly by
a) Burning of fossil fuels
b) Respiration
c) Photosynthesis
d) Fungi
Answer:- c) photosynthesis
Photosynthesis is the process of plants for making food . In these process plants use Carbon dioxide and sunlight to make food and release oxygen as by product. Which returned into atmosphere
25) Low visibility during cold weather is due to
a) Formation of fossil fuels
b) Unburnt carbon particles or hydrocarbons suspended in air
c) Lack of adequate power supply
d) None of these
Answer:- b) unburnt carbon particles or hydrocarbons suspended in air
The smog or fog formed in the winter morning Reduces the visibility. The unburnt Carbon particles or hydrocarbons suspended in air forms the fog.
26) Growth of lichens on barren rocks is followed by the growth of
a) Moss
b) Ferns
c) Gymnosperms
d) Algae
Answer:-a) moss
Growth of lichens on the barren rocks is followed by the growth of moss because lichens release some enzymes on the rock which helps in growth of moss.
27) Marked temperature changes in aquatic environment can affect
a) Breeding of animals
b) More growth of aquatic plants
c) Process of digestion in animals
d) Availability of nutrients
Answer:- a) Breeding of animals
Breeding of animals dependent upon the temperature because mostly aquatic animals are cold blooded animals thus eggs and larvae are sensitive to the temperature.
28) Soil erosion can be prevented by
a) Raising forests
b) Deforestation
c) Excessive use of fertilizer
d) Overgrazing by animals
Answer:- a) Raising forests
Roots of trees prevent the soil from flowing with flood also the shadow of the trees prevent the top soil from heating and thus forests prevent soil erosion.
29) What happens when rain falls on soil without vegetation cover ?
a) Rain water percolates in soil efficiently
b) Rain water causes loss of surface soil
c) Rain water leads to fertility of the soil
d) Rain water does not cause any change in soil
Answer:- b)Rain water causes loss of surface soil
Rain water turns into floods and these flow away with the upper layer of soil. Thus it causes the loss of soil surface. If the vegetation is covered over the soil then the roots bind the soil particles with it which does not allow the soil to flow with it .
30) Oxygen is harmful for
a) Ferns
b) Nitrogen fixing bacteria
c) Chara
d) Mango tree
Answer:- b) Nitrogen fixing Bacteria
Anaerobic bacteria does not need oxygen, bacteria is killed when get in contact with the oxygen and nitrogen fixing bacteria is anaerobic in nature.
Short Answer Questions
31) Rivers from land , add minerals to sea water. Discuss how?
Answer:- When the rovers flows or when the flood comes it flows all the top layer soil with the water. Top layer soil contains most of the minerals, and nutrients of the soil, which is required by the plant for growing . But all these top layer soil gets flown with water which converted into river and then these rivers get joined to sea water.
32) How can we prevent the loss of top soil?
Answer:- Open fields are very much affected by the soil Pollution and top layer of soil loss the nutrients and therefore when the top soil is covered by trees then the roots of soil hold the soil and minimizes the pollution of soil. loss of top soil can be prevented by planting trees, Changing irrigation methods and trying crop rotation in agricultural lands.
33) How is the life of organisms living in the water affected when water gets polluted?
Answer :- polluted water contains many harmful chemicals, and fertilizers. When these components are added to water then water becomes contaminated and many diseases causes by such water. These type of water not only harms the humans but also harms the aquatic animals. Aquatic animals needs oxygen from the water but these pollutants added to water decrease the dissolved oxygen in water.
34) During summer, if you go near the lake, you feel relief from heat, why?
Answer:- In the summer days temperature is very high and thus we feels hot over the land. Lake filled with water starts evaporating due to high temperature which leads to cooling . Thus we feel cool near Lake.
35) 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:- At the day time, due to sun land heats more but at the same time water in sea evaporates and that evaporation leads to cooling. Thus the breeze move from lower temperature i.e from sea to higher temperature to cool the land. And at night water remains warm for longer time but land gets cool faster thus the air breeze move again from lower temperature to the Higher temperature. That is from land to sea.
36) Following are a few organisms
a) Lichen
b) Mosses
c) Mango tree
d) Cactus
Which of the above can grow on stones, and also in formation of soil? Write the mode of their action for making soil.
Answer:- Lichen and mosses can grow on the stones and also help in the formation of soil. Mosses are grown due to the lichens enzymatic action over the rock. Moses turns the rocks into soil.
37) Soil formation is done by both biotic and abiotic factors. List the names of these factors by classifying them as abiotic and biotic?
Answer:- biotic factors help in the soil formation are – Trees, lichens and Mosses
Abiotic factors help in the soil formation are – Water, sun, wind, temperature
38) 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:- Yes, all the organisms contains these elements in some parts of our body, some elements we get from our food what we eat. Mainly from vegetables. We breath in the oxygen. Sulphur, phosphorus, carbon, nitrogen and hydrogen all these we get mainly through vegetables. Nitrogen comes from nitrogen fixation, hydrogen and oxygen from water, phosphorus and Sulphur from absorption from soil, and carbon from photosynthesis.
39) Why does the percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere?
Answer:- Percentage of oxygen , nitrogen and carbon dioxide remain same in the atmosphere because the environmental cycle maintain the equilibrium of these gases.
40) Why does moon have very cold and very hot temperature variations eg, from – 190°c to 110° c even though it is at the same distance from the sun as the earth is ?
Answer:- Moon does not have the atmosphere present over there as like earth. Earth has atmosphere which maintains the temperature and these prevent the earth’s environment from excessive and lowest temperature. The gases present on the earth like Carbon and water vapour etc. Are responsible for the maintaining the temperature.
41) Why do people love to fly kites near the seashore?
Answer:- Sea breeze during the day time is very much suitable for the flying kites, thus people love to fly kites near sea shore.
42) Why does mathura refinery pose problems to the Taj Mahal ?
Answer:- The factories near the agra and Mathura are realising the toxic gases like sulphur oxides and nitrogen oxide, these gases combines with the raining water and turns into the acid. These phenomena is known as acid rain. These acid rain is responsible for the yellowish spotting of the marble of Taj mahal.
43) Why do not lichens occurs in delhi whereas they commonly grow in Manali or Darjeeling ?
Answer:- Delhi has high level of pollution and many dangerous gases along with the sulphur oxide is released by automobiles. But Lichen is sensitive to the sulphur oxide hence it does not grow in the Delhi. Where as manali and Darjeeling has low level of Pollution and does not have number of vehicles which are responsible for pollution hence the level of sulphur oxide is low in the atmosphere. Thus lichens grows in the manali and Darjeeling and not in delhi.
44) Why does water need conservation even though large Oceans surround the land masses?
Answer:- We should conserve the fresh water resources for the betterment of humans and plants because Large Oceans and sea water is not useful for humans for drinking. It contains high level of salt. Which is also not suitable for the plants.
45) There is mass mortality of fishes in a pond. What may be the reasons?
Answer:-
The reasons for the mass mortality of fishes in a pond may be –
- the contaminated water containing the harmful chemicals, fertilizers, pesticides, herbicides etc.
- addition of mercury in to the water bodies lead to the death of fishes.
- The pollutants added to the water body can enter the fishes and block the gills which damage the respiration of fishes.
46) Lichens are called pioneer colonisers of bare rock. How can they help in formation of soil?
Answer:- Lichens are found over the rocks these lichens release the enzymes on the rocks. These enzymes causes the action the rock and rocks breaks into smaller pieces. These procedure becomes responsible for the formation of soil.
47) “ Soil is formed by water.” If you agree to this statement then give reasons
Answer:- Yes, for the formation of soil water has a big role. Rocks gets brittle after a longer exposure of water, it causes rocks to break into smaller pieces. after alternate exposure of sun-light and rain rocks breaks into small size and it finally forms the soil after several years.
48) Fertile soil has lots of humus, why?
Answer:- Humus is very important for the plants as it contains the nutrients and minerals. It also helps the soil for porous structure, and it makes water absorption easily. The fertile soil has microorganisms which converts The organic matter and decomposed matter into humus. Thus fertile soil has lots of humus.
49) Why step farming is common in hills?
Answer:- Hills have slops which so can be dangerous in the rainy season as the water takes out the soil with it. These can also takes the crop with the water coming down from the hills. The steps made in the hills for the farming prevent the crops and top layer of soil from flow away with water.
50) Why are root modules useful for the plants?
Answer:- Every plant needs nitrogen for their growth. The root nodules contains the bacteria such as Rhizobium. These Rhizobium is the nitrogen fixing bacteria which fixes the nitrogen naturally in the plants. Thus root nodules are useful for plants.
Long Answer Questions
51) How do fossil fuels cause air Pollution?
Answer:- The burning of fossil fuels leads to air Pollution. Fossil fuels contains petrol diesel , kerosene , wood, coal letc product. These after burning Releases gases like sulphur, Carbon, carbon monoxide, and nitrogen. The suspended particles in the air leads to harmful effects on the humans body.
52) What are the causes of water Pollution? Discuss how you can contribute in reducing water Pollution.
Answer:-
There are many water Pollution such as-
- Directly throwing of sewage into the water bodies.
- Waste water from the factories
- Fertilizers and pesticides which includes several chemicals reached to the water bodies.
- Dust and soil blow out with wind or flood makes the water impure.
To reduce the water Pollution we can take the following measures –
- Do not throw sewage into water. Pass it through the sewage treatment plant.
- Avoid throwing domestic waste into into water bodies.
- Avoid throwing chemical waste like Fertilizers into the water.
53) A motor car, with its glass totally closed, is parked directly under the sun. The inside temperature of the car rises very high. Explain why?
Answer:- The temperature of the car parked under the direct sun is rises due to the infrared rays passing through the glasses in the car.
54) Justify “ dust is a pollutant”?
Answer:- Dust is also known as pollutants because it is a waste particles of soil which flew away with air or wind and these enters the body of humans via nasal cavity which causes allergies. Also the dust particles blocks the stomatal opening of plants. Dust particles are the waste products which infect the water bodies and food in the open. These causes several diseases to humans . Hence it is called as pollutant.
55) Explain the role of the sun in the formation of soil.
Answer:-Sun has very much important role in the formation of soil along with the rain. Rain and sun alternately work on the hard rocks and transform them into soil after several years. The temperature of sun-light heat the rocks and then it cools in the night so the rocks get cracks and forms soil after several years.
56) Carbon dioxide is necessary for plants. Why do we consider it as a pollutant?
Answer:- Co2 is necessary for plants but in limited quantity if the level of carbon dioxide increased in the environment it also has an harmful effects over the growth of plants. Along with that Co2 is an green house gas which leads to the global warming effect. It helps in the Increasing the temperature of the earth and thus excess of carbon dioxide is dangerous for the earth. Hence it is named as pollutant.
Here is your solution of NCERT Exemplar Solution Class 9 Science Chapter 14 Natural Resources .
Dear Student, I appreciate your efforts and hard work that you all had put in. Thank you for being concerned with us and I wish you for your continued success.