Please refer to Natural Resources Chapter 14 Class 9 Science Assignments below. We have provided important questions and answers for Natural Resources which is an important chapter in Class 9 Science. Students should go through the notes and also learn the solved assignment with solved questions provided below. All examination and class tests questions are as per the latest syllabus and books issued by CBSE, NCERT, and KVS. We have also provided Class 9 Science Assignments for all chapters on our website.
Chapter 14 Natural Resources Class 9 Science Assignments
Question. Name two biologically important compounds that contain both oxygen and nitrogen.
Proteins and nucleic acids (DNA and RNA).
Question. The atmosphere acts as a blanket, how?
Air is a bad conductor of heat which keeps average temperature of the Earth steady during day and at night. The ozone shield of the atmosphere absorbs most of the harmful radiations coming from Sun.
Question. List any two traditional systems of water harvesting.
Two traditional systems of water harvesting are :
Collection of water in ponds and construction of small Earthen dams.
Question. Define anaerobic degradation.
Breakdown of organic matter by microorganisms when oxygen is not present is known as anaerobic degradation.
Question. Name the three processes which used oxygen.
Combustion, respiration and in the formation of oxides of nitrogen.
Question. What is the greenhouse effect?
Some gases prevent the escape of heat from the Earth.An increase in the percentage of such gases in the atmosphere would cause the average temperatures to increase worldwide and this is called the greenhouse effect.
Question. Give two natural resources available on the Earth.
Water and air.
Question. State two reasons each of conserving (a) forest and
Two reasons each of conserving :
(i) It helps in retaining the sub-soil water.
(ii) It checks flood.
(i) To maintain ecological equilibrium.
(ii) To protect the nature.
Question. 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?
Absence of atmosphere on the Moon.
Question. Identify which of the following are not the part of biotic environment : soil, plants, fish, air, insects.
Question. Name two oxides formed by burning of fossil fuels, which are responsible for acid rain.
The oxides of nitrogen and sulphur :
(i) Sulphur dioxide and sulphur trioxide.
(ii) Nitrous oxide and nitrogen dioxide.
Question. State an instance where human intervention saved the forests from destruction.
Answer. Human intervention saved the Arabari forest range of West Bengal from destruction with active and willing participation of local community. The Sal forest of Arabari underwent a remarkable recovery.
Question. What are the consequences of global warming?
(i) An increase in temperature of Earth even by 1°C may lead to melting of ice on the poles.
(ii) The melting of ice will result in rise of sea level.
(iii) Due to rise in sea level, many coastal cities will be flooded or submerged.
(iv) Increase in temperature of Earth, results the changes in weather and may cause excessive raining or drought or extreme hot or cold weather conditions.
Question. What is ozone hole? Where is it found? What is its effect?
Answer. There is a layer of ozone in the upper regions of the atmosphere which gets depleted due to chlorofluorocarbons and created a hole that is called ozone hole. It is found above North Pole.
Question. Which cycle is known as the perfect cycle in biosphere? Why?
Answer. Nitrogen cycle is known as the perfect cycle in biosphere as it maintains the amount of nitrogen in atmosphere, water and soil.
Question. How is reuse better than recycling?
Answer. ‘Sustainable management’ is the management of resources in which development can be maintained for a long time without undue damage to the environment.Recycling needs additional energy to make a usable item. Reuse does not require additional energy and hence, is better than recycle.
Question. How did ‘Chipko Andolan’ ultimately benefit the local people? Describe briefly.
Answer. Chipko Movement :
(i) During 1970, in Reni village of Garhwal, a contractor was allowed to cut trees in a forest near the village.
(ii) When the contractor’s workers went to the forest to cut trees, the women of the village hugged the tree trunks to prevent the workers from cutting trees.
(iii) Chipko means ‘hug’ and the movement began with the villagers hugging trees. It is called the ‘Chipko Andolan’.
(iv) The movement benefited the local population as it conserved the forest products. It benefited the environment as it conserved the quality of soil and sources of water thereby, maintained balance in nature.
Question. Name four human activities which cause air pollution.
Answer. Mining : Mining activities release dust.
Thermal power plants : Air pollution caused by burning of fossil fuel.
Firework on festivals : It results in the release of toxic chemicals into air.Burning of fossil fuel : In industries, automobiles,domestic purposes, etc.
Question. Name the stages of the life cycle of aquatic animals which are affected by change in temperature.
Answer. The eggs and larvae of various aquatic animals are sensitive to temperature changes. Sudden change in the temperature in the water body would be dangerous for them or affect their breeding.
Question. Which of the two is a better option, (i) to collect rainwater in ponds or artificial lakes, or (ii) to let it recharge groundwater by water harvesting? List two advantages of the option to justify your Answer.
To allow rainwater to recharge groundwater by water harvesting is the better option. Its advantages are :
(i) Groundwater does not evaporate.
(ii) Groundwater does not provide breeding ground for mosquitoes.
Question. How is soil formed?
Answer.The rocks near the surface of the Earth are broken down by various physical, chemical and some biological processes over long periods of time, thousands and
millions of years. Finally, fine particles of soil formed.There are many other factors which play a vital role in the formation of soil. These factors are :
(i) The Sun heat, (ii) Water, (iii) Wind, (iv) Living organisms.
Question. List any two causes of our failure to sustain availability of underground water.
Answer. Two causes of our failure to sustain availability of underground water are :
(i) Rising population : As the population increases, demand for water increases resulting in depletion of underground water level.
(ii) Industrialization : Industries need more and more water to manufacture products. With growing industrialization, demand for water increases which results in reduction in the availability of underground water.
Question. Define biosphere. Name its components.
Answer. Biosphere is global ecological system integrating all living beings and their relationships, including their interaction with the elements of lithosphere, geosphere, hydrosphere and atmosphere. The two components of biosphere are :
(i) Biotic : All living organism such as plants, animals and microorganisms.
(ii) Abiotic : Air, water and the soil.
Question. Do you know any activity which may be polluting water sources?
There are many activities which cause pollution of water sources such as :
(i) Dumping of waste from factories, sewage from our towns and cities into rivers,
(ii) Discharging polluting water from cooling towers into the water bodies affects the breeding capacity of aquatic organisms.
Question. What are the different states in which water is found during the water cycle?
Three different states of water can be seen during the water cycle. These states are :
(i) Gaseous state : Form of water vapour which evaporates from the surface water,
(ii) Liquid state : Formed by the condensation of water vapour and can be seen in the form of rain,
(iii) Solid state : Formed by the freezing of liquid droplets in the upper layer of atmosphere which can be seen in the form of snow, hail.
66. What causes winds?
Answer. Winds are caused due to uneven heating of atmospheric air. This phenomenon can be seen near coastal regions during the daytime. The air above the land gets heated faster and starts rising. A region of low pressure is created as this air rises, and air over the sea moves into this area of low pressure. The movement of air from one region to the other creates winds. During the day, the direction of the wind would be from the sea to the land.
Question. “Soil is formed by water.” If you agree to this statement then give reasons.
Water helps in the formation of soil in the following ways :
(i) Water causes ‘wear off’ of rocks over a long period of time.
(ii) It also causes the rocks to rub against other rocks creating small particles which are taken away downstream and deposited as soil.
(iii) Water expands on freezing in crevices of rocks and break rocks into smaller pieces.
Question. What causes movement of air? Mention the factors which influence these winds?
(i) Uneven heating of the atmosphere.
(ii) Rotation of the Earth.
(iii) Presence of mountain range.
(iv) Difference in cooling and heating of land and water bodies.
(v) Formation and condensation of water vapours.(any two)
Question. How is the atmosphere of Venus/Mars different from that of the Earth? Name two main gases present in Earth’s atmosphere.
Question. What are the adverse effects of products of combustion of fossil fuels on the environment?
Answer. When fossil fuels are burnt, carbon dioxide, water,oxides of nitrogen and oxides of sulphur are formed.If the combustion takes place in insufficient air, then carbon monoxide is formed instead of carbon dioxide. Of these products, the oxides of sulphur and nitrogen and carbon monoxide are poisonous gases and carbon dioxide is a greenhouse gas.
Question. What is ‘Chipko Movement’? Why should we conserve forests?
Answer. ‘Chipko Movement’ is a non-political public movement for conservation of natural habitat and wildlife by preventing excessive commercial exploitation of forests. Chipko means ‘hugs’ and the movement were started by the villagers of Garhwal by hugging trees to stop the contractor’s workers from cutting the trees. We should conserve forests because it helps in protection of land, retaining sub-soil water, checking floods, and thereby maintain a balance in the ecosystem.
Question. Give two examples each of the Renewable sources of energy and Non-renewable sources of energy.
(i) Geothermal energy, wind energy
(ii) Coal, petroleum
Question. Write any four advantages of water stored in the ground.
Answer. Four advantages of storing water in the ground are :
(i) It does not evaporate.
(ii) It is relatively protected from contamination by
human and animal wastes.
(iii) It does not provide breeding ground for mosquitoes.
(iv) It provides moisture for vegetation.
Question. What is meant by exploitation of resources with shortterm aims? List its four advantages.
Answer. Exploitation of resources with short-term aims means consumption of resources for immediate requirement without their conservation for future. Its four advantages are :
(i) It fulfils the requirement of mass population.
(ii) It provides industrial growth.
(iii) It provides economic development.
(iv) It makes life comfortable.
Question. Define weathering. Write the different means which cause weathering.
Answer. The process of breaking down of rocks into small, fine mineral particles is called weathering. The weathering may occur due to physical, chemical or biological means.
Question. Why must we conserve our forests? List any two causes for deforestation to take place.
Answer. We must conserve our forests as they are of great value. The reasons for conserving forests are :
(i) Forests help in protection of land and retaining sub-soil water.
(ii) Forests check floods and maintain ecosystem.
Therefore, forests must be conserved for economic and social growth.
Two causes for deforestation taking place are :
(i) For industrial needs.
(ii) For development projects like building of roads or dams.
Question. Name any two forest products, each of which is the basis for some industry.
(i) Pine wood for matchbox industry.
(ii) Bamboo for paper industry.
Question. Describe how lichens and big trees influence the formation of soil.
(i) Lichens grow on the surface of rocks and release substances that breaks down the rock surface.
(ii) Moss grows on this surface and breaks it further.
(iii) The roots of trees grow into rocks, form cracks and widen them further to form soil.
Question. State two changes you can make in your habits to reduce the consumption of electricity or water.
Answer. Two changes that can be made to reduce the consumption of electricity or water are :
(i) Switch off lights and fans when not in use.
(ii) Leaked taps should be repaired immediately.
Question. List the causes that affect the life forms that are found in water bodies in various ways. Name the element present in coal other than carbon that releases harmful gases during combustion of coal.
(i) Excess of fertilizers and pesticides used in the farms are washed into water bodies.
(ii) Dumping of sewage from dwelling places into water bodies.
(iii) Release of contaminated water from industries.
(iv) Release of water from dams affects the temperature of river.
(v) Sulphur and nitrogen.
Question. Give any four changes that you would like to incorporate in the lifestyle of students of your age to move towards a sustainable use of available resources.
(i) Follow the principle of three ‘R’s – Reduce,Recycle and Reuse.
(ii) Plant more trees.
(iii) Use public transport, school bus and car pools.
(iv) Switch off unnecessary lights and fans, thereby save electricity.
Question. List any four benefit of water harvesting.
Answer. Benefits of water harvesting are :
(i) It provides drinking water.
(ii) It provides irrigation water.
(iii) It is responsible for the increase in groundwater level.
(iv) It reduces storm water discharge, urban flood and overloading of sewage treatment plants.
Question. What are the methods of preventing or reducing soil erosion?
Answer. The methods of preventing soil erosion are :
(i) Afforestation : Plants reduce erosion as the roots of plants bind the soil in place.
(ii) Shelter belts : Trees planted in lines around farmland reduce erosion by reducing the speed of the wind.
(iii) Contour ploughing : Farmers plough land so that furrows lie across the natural slope of the land which do not allow it to flow down carrying the topsoil.
(iv) Terrace farming : A terraced hillside is a series of steps formed by horizontal strips supported by walls. It gives the water sufficient time to percolate into the soil and nourish the crop.
(v) Soil cover : Soil left bare after harvesting a crop is often covered with dried vegetation to prevent erosion.
(vi) Preventing overgrazing : Even a very little grass on a field prevents erosion of soil as the grass has a tendency to bind soil molecules.
Question. Write a note on “how forests influence the quality of our air, soil and water resources”.
Answer. Forests influence the quality of air, soil and water resources in the following ways :
(i) Influence of forests in controlling the quality of air:
(a) Forests help in minimising the level of CO2 in the atmosphere which help to reduce greenhouse effect and global warming.
(b) Forests reduce environmental temperature which increases the rate of photosynthesis in plants in the surrounding regions.
(c) Some of the trees have the ability to absorb harmful gases present in the atmosphere, e.g., Jamun trees can absorb compounds of lead easily.
(ii) Influence of forests in controlling the quality of soil :
(a) The roots of trees prevent erosion of topsoil
(b) Forests also regulate biogeochemical cycles
(c) Many of the decomposing bacteria and nitrogen-fixing bacteria live in close association with the roots of the trees.
(iii) Control the quality of water :
(a) Forests help in returning pure water back to the surface of Earth through rains.
(b) Forests help in maintaining the water cycle as well as water resources of the Earth.
Question. Mention any three human activities which are responsible for water pollution.
(i) Excessive use of fertilizers and pesticides.
(ii) Disposal of industrial waste which contains poisonous substances into nearby water bodies.
(iii) Sewage discharged into sewers from household/ domestic units.
(iv) Synthetic soap and detergents used during washing in household units.
(v) Hot water released from industrial units.
Question. (a) Explain the formation of acid rain.
(b) What does the presence of smog in an area indicate?
(a) Acid rain is the rainwater which have excessive amount of acids/i.e., sulphuric acid and nitric acid.
These acids are formed by the reaction of oxides of sulphur and nitrogen with water.
The oxides of sulphur and nitrogen are produced by combustion of fossil fuels in industries, automobiles, thermal power plants and domestic appliances, etc.
The sulphur and nitrogen, present in fossil fuels form these oxides by reacting with oxygen of air by the process of combustion.
(b) The presence of smog in an area indicates the high percentage of smoke released in the air by combustion of fossil fuel in industries or automobiles. It is an indicator of air pollution.
Question. (a) What is the outermost layer of our Earth called?
(b) How is this important to life forms?
(c) Name four factors that help in the formation of soil from rocks.
(a) The outermost layer of our Earth is called crust.The outer crust of Earth is called lithosphere.
(b) The living forms get all substances of their requirement for supporting life form this region.
(c) (i) Winds,
(iii) Living organisms,
(iv) Temperature variations (due to solar radiation).
Question. How does nitrogen fixation take place during lightning?How do plants make use of the nitrates and nitrites present in soil?
Figure: Nitrogen Cycle in Nature
The high temperatures and pressure created in the air convert nitrogen into oxides of nitrogen during lightning. These oxides dissolve in water to give nitrous and nitric acids that fall on land with rain.Nitrogen fixing bacteria which are found in the roots of leguminous plants convert atmospheric nitrogen into nitrate (the usable form by plants).The plants use nitrogen in the form of nitrates and nitrites to form amino acids and proteins. The plants are used as food by animals.
The bacteria convert these compounds of nitrogen into nitrates and nitrites, after the death of plants and animals.
Some other types of bacteria convert nitrites and nitrates into molecular nitrogen, which escapes into atmosphere and becomes a part of it.
Question. ‘A change in temperature in the water body affects aquatic organisms.’ Explain in brief.
Change in the water temperature can affect the aquatic life in the following ways : It can encourage the growth of some life forms and harm some other life forms. This affects the balance between various organisms which had been established in that system.This can lead to removal of desirable substances like oxygen and other nutrients from water bodies.
The eggs and larvae of various animals are particularly susceptible to temperature changes.So such aquatic life forms may become extinct from the related water bodies. Thus, the breeding of aquatic organisms will be affected.
Question. Write in brief the harmful effects of water pollution.
(i) Causes water borne disease.
(ii) Destroys microorganisms thereby affecting self purification of water.
(iii) Decreases amount of dissolved O2 in water bodies.
(iv) Changes the temperature of water, oceans, leading to melting of polar ice.
(v) Disturbs aquatic life.
(vi) Kills aquatic organisms.