Natural Resources Chapter 14 Class 9 Science Worksheets

Students should practice questions given in Natural Resources Chapter 14 Class 9 Science Worksheets. These worksheets for Class 9 Science have a good collection of important questions and answers which are expected to come in your class tests and examinations. You should learn these solved worksheet questions for Science Class 9 as it will help you to understand all topics and give you more marks.

Class 9 Science Worksheets Chapter 14 Natural Resources

Please refer to below questions and answers for Natural Resources Chapter 14 Class 9 Science Worksheets. Prepared by expert teachers for Standard 9 Science

Question. Name two gases which cause greenhouse effect.

Question. Write one example of biotic component of the biosphere.

Question. Mention the two forms of precipitation in nature when the temperature of air is very low.

Question. Name the factor responsible for change in rainfall patterns in India.

Question. What is the function of humus in soil?

Question.Combustion of fossil fuels results in the increase of suspended particles in the air. What are these particles?

Question. How the frozen water between cracked rocks causes the cracks to widen?

Question. Name two biologically important compounds that contain both oxygen and nitrogen.

Question. Name two essential biological molecules in which oxygen is present.

Question. What is the importance of carbon cycle?

Question. Why does the percentage of gases like oxygen, nitrogen and carbon dioxide remain almost the same in the atmosphere?

Question. Dron took some soil in a beaker and added some water in it. Then stir with glass rod.
(a) What do you think Dron observed?
(b) What does her observation demonstrate?
Answer.
(a) Bubbles coming out the soil.
(b) Practical shows that air is present in the soil. It also shows that air in the porous space between the soil particles is replaced by water.

Question. What are the two forms of oxygen found in the atmosphere?
Answer.
(i) Elemental oxygen is normally found in the form of a diatomic molecule (O₂) in the lower regions of the atmosphere to the extent of 21%. It is nonpoisonous form of oxygen.
(ii) But in the upper part of the atmosphere (stratosphere), it occurs in the form of ozone, containing three atoms of oxygen and having the molecular formula O₃. It is the poisonous form of oxygen.

Question. Why are forests considered “biodiversity hotspots”? List two ways in which an individual can effectively contribute to the management of forests and wildlife.
Answer. Biodiversity is measured by the number of different life forms found in an area. In a forest, various species exist which include bacteria, fungi, ferns, plants, nematodes, insects, birds, reptiles and mammals.Forests are, therefore, considered as biodiversity hotspots. An individual can contribute in the management of forests and wildlife by :
(i) Avoiding cutting down of forests and killing of wildlife
(ii) Educating people about the importance of forests and wildlife in our life.

Question. How do Sun and wind influence the formation of soil?
Answer. Sun : The Sun heats up rocks during the day to expand the rocks and at night they cool down and contract.This result in the formation of cracks and rocks finally break up into smaller pieces.
Wind : Strong winds help in the formation of rock particles by their erosion. This helps in formation of soil.

Question. Write the composition of soil. On what basis is the type of soil decided?
Answer. Soil is a mixture and composed of small particles of rocks of different sizes, humus and various microorganisms. The type of soil is decided by the average size of particles found in it.

Question. How is soil formed? List four factors which play a vital role in the formation of soil.
Answer. Soil is formed by breakdown of rocks by various physical, biological and chemical processes. Following factors play important role in the formation of soil :
(i) Temperature variations due to solar radiation,
(ii) Rainwater,
(iii) Wind,
(iv) Living organisms.

Question. What is the major source of freshwater in the city/ town/village where you live?
Answer. The major source of freshwater in the city is the underground water which is mostly taken out with the help of hand pumps. The rivers lakes and ponds flowing in the nearby areas also serve as the source of freshwater.

Question. What is soil erosion?
Answer. The removal of topsoil which is rich in humus and nutrients by flowing water or wind is known as soil erosion. All soil may get eroded if this process continues further. It may lead to the loss of all valuable resources because nothing grows as such on the rocks.

31. What are the different ways in which water gets polluted? How does it affect the life forms?
Answer. The addition of undesirable substances like fertilizers and pesticides, mercury salts in water/can cause cholera produced by the bacteria.
The removable of desired substances like oxygen from the water/adversely affect the aquatic organisms.A sudden change in temperature in water bodies/ would be dangerous and affect their breeding. The eggs and larvae are affected by the change in temperature.

Question. What are the biogeochemical cycles? Name the gas that is incorporated into life forms through photosynthesis.
Answer. The transfer of energy and matter between the biotic components of the biosphere is called biogeochemical cycle. The gas that is incorporated into life forms through photosynthesis is carbon dioxide.

Question. Explain how the nitrogen molecules are converted into nitrates and nitrites by :
(i) Biological process,
(ii) Physical process.
Answer.
(i) Biological process : Nitrogen fixing bacteria found in the root nodules of the legumes convert nitrogen molecules to nitrates and nitrites.
(ii) Physical process : The high temperature and pressure created in the air convert nitrogen into oxides of nitrogen during lightning.

Question. What is meant by sustainable management? The environmentalists are insisting upon “sustainable natural resource management”. State its four advantages.
Answer.Sustainable management is the management of natural resources which requires a long-term perspective so that they last for generations to come and are not to be exploited by the short-term gains. Its four advantages are as follows :
(i) Resources last for a longer duration.
(ii) It provides steady economic growth.
(iii) It helps in ecological conservation.
(iv) It reduces pollution.

Question. What is the main cause of increase in CO₂ in atmosphere? Explain the harmful effect of increase in CO₂ content in atmosphere.
Answer. The main cause of increase in carbon dioxide in the atmosphere is industrial revolution. Increase in carbon dioxide gives rise to greenhouse effect and global warming. This causes imbalance in nature, affects monsoons and rainfall.

Question. Name the various organisms involved in nitrogen cycle.
Answer.
(i) Nitrogen fixing bacteria, e.g., Rhizobium,Azotobacter.
(ii) Bacteria which convert complex nitrogenous organic compounds (proteins) into ammonia, e.g.,Actinomyces.
(iii) Nitrifying bacteria that convert ammonia into nitrates, e.g., Nitrosomonas and nitrobactor.
(iv) Denitrifying bacteria, e.g., Pseudomonas.

Question. What are the three ways by which CO₂ is returned back into atmosphere?
Answer.
The three ways by which CO₂ is returned back into atmosphere are :
(i) Decomposition of dead organic matter.
(ii) Respiration by both plants and animals.
(iii) Formation of gaseous waste by the combustion of fuels like coal, wood and petrol.

Question. How do advantages of exploiting natural resources with short-term aims differ from the advantage of managing our resources with a long-term perspective?
Answer. Exploiting resources with short-term aim is just to reap huge profit, whereas using resources with a longterm perspective is to reap the benefit in a sustainable manner so that these will last for generations to come.

Question. “Burning fossil fuels is a cause of global warming.” Justify this statement.
Answer. Fossil fuels like coal and petroleum are formed from biomass. In addition to carbon, they contain hydrogen, nitrogen and sulphur. When fossil fuels are burnt, the products are carbon dioxide, water vapour, oxides of nitrogen and oxides of sulphur. Carbon dioxide is a greenhouse gas. Increase in the percentage of carbon dioxide increases the temperature on Earth which leads to global warming.

Question. Mention three ways by which atmosphere regulates the average temperature on Earth.
Answer.
(i) As the air is a bad conductor of heat, therefore, the atmosphere keeps the average temperature of the Earth fairly steady during the day even during the course of the whole year.
(ii) The atmosphere prevents the sudden increase in temperature in day time.
(iii) It slows down the escape of heat into the outer space.

Question. Mention any three important roles of water required for organisms on the Earth’s surface.
Answer.
(i) All cellular processes take place in water medium.
(ii) Water regulates body temperature.
(iii) Water is required for transportation of nutrients from one part of the body to the other.

Question. What are the various causes of soil erosion?
Answer. Causes of Soil Erosion :
(i) Wind – Carrying away the topsoil
(ii) Rain – Unprotected topsoil by washing it down
(iii) Improper farming
(iv) Frequent flooding of rivers causes soil erosion
(v) Deforestation

Question. (a) Explain, how soil pollution is caused?
(b) Write three ways to prevent soil pollution.
Answer.
(a) The soil pollution may be caused by throwing the industrial wastes in vacant sites viz., along the roads, railway tracks, etc. The wastes from residences, cattle sheds, industries, agricultural fields, etc. also pollute the soil. The excessive use of fertilizers and pesticides pollutes the soil.
(b) Three ways to prevent soil pollution :
(i) By judicious use of fertilizers and pesticides
(ii) By proper management of disposal of household waste
(iii) Terrace farming should be practiced

Question. List any four characteristics of a good fuel.
Answer.
(i) Higher calorific value
(ii) Lesser pollution
(iii) Sustainable for longer period
(iv) Easily transportable

Question. Explain the following terms :
(i) Nitrogen fixation,
(ii) Nitrification,
(iii) Denitrification.
Answer.
(i) The process in which atmospheric nitrogen is converted into usable forms like ammonia,nitrates, nitrites or NO₂, etc. is called nitrogen fixation.
(ii) The process of formation of nitrites and then to nitrates from ammonium compounds is called nitrification.
(iii) The process of conversion of some ammonium compounds, nitrites and nitrates into molecular nitrogen is called denitrification.

Question. In what forms the water is found on the Earth’s surface? Describe in brief.
Answer. Most of the water on Earth’s surface is found in the form of liquid in seas, oceans, rivers, lakes, ponds, etc.It is found in the form of ice (solid) in the ice-caps on mountain peaks and in Polar Regions. Water is also found in vapour state when it evaporates at the surface of water bodies, as moisture in the atmosphere, air transpired by plants and air exhaled by animals.

Question. Why is the atmosphere essential for life?
Answer. Atmosphere is essential for life because of the following reasons :
a. It keeps the average temperature of the Earth
b. It prevents the sudden increase in temperature
c. It contains all the important gases which are required for sustaining life on Earth. These gases are :
(i) Oxygen for respiration of living organisms
(ii) Carbon dioxide for photosynthesis
(iii) Nitrogen for providing inert atmosphere
(iv) Ozone layer to filter the harmful UV radiation from Sun

Question. (a) In what ways the water cycle helps the marine organisms?
(b) ‘The biosphere is a dynamic but stable system.’Justify this statement.
Answer.
(a) (i) Water is capable of dissolving a large number of substances.
(ii) Water flows through rocks containing soluble minerals.
(iii) Some of the minerals get dissolved in the water which is carried by water bodies and made available to aquatic organisms.
(b) (i) There is a constant interaction between the biotic and abiotic components of the biosphere.
(ii) These interactions consist of a transfer of matter and energy between the different components of the biosphere and make it a dynamic but stable system.

Question. Write the name of triatomic molecule of oxygen. Is its presence necessary in nature? How does it affect the environment? Explain.
Answer.
(i) The triatomic form of oxygen is called ozone.
(ii) Yes, its presence is necessary in nature.
(iii) Ozone absorbs the harmful radiations from the Sun and, thereby protects many forms of life from getting damaged.

Question. Fertile soil has lots of humus. Why?
Answer. Fertile soils are rich in organisms that decompose dead organic matter forming humus. Humus gives minerals, absorbs water and makes soil porous.

Question. Define the terms :
(i) Soil, (ii) Paedogenesis.
Answer.
(i) Soil : It is the humus containing and life sustaining weathered uppermost crust of Earth.
(ii) Paedogenesis : The process of formation of soil is called paedogenesis.

Question. Give two examples where oxygen is not playing any role in supporting life.
Answer.
(i) Some bacteria are poisoned by elemental oxygen.
(ii) The process of nitrogen-fixing by bacteria does not take place in the presence of oxygen.

Question. List any four disadvantages of using fossil fuels for the production of energy.
Answer.
Disadvantages :
(i) Fossil fuels cause pollution.
(ii) They also cause acid rain.
(iii) They disturb ecology.
(iv) They cannot be reused, i.e. they are nonrenewable.

Question. Suggest three ways to maintain a balance between environment and development to survive.
Answer. The three ways to maintain a balance between environment and development to survive are as follows:
(i) Forest resources should be used in an environment friendly and developmentally sound manner.
(ii) Instead of using non-renewable natural resources, use of renewable natural resources should be preferred.
(iii) Waste water generated by industries should be recycled.
(iv) We should use natural resources cautiously so that economic growth and ecological conservation go hand in hand.

Question. List any three human activities which would lead to an increase in the carbon dioxide content of air.
Answer. Three human activities which would lead to an increase in the CO₂ content of air are :
(i) Respiration : It is the natural process of release of CO₂ by both plants and animals.
(ii) Combustion of fuels : The various types of fuels are burnt to provide energy for various, needs like heating, cooking, transportation and industrial fuels.
(iii) Deforestation : Trees help in the conversion of CO₂  into organic compounds such as glucose, starch, etc., by the process of photosynthesis but deforestation disturb this process and increase the level CO₂  increases in our environment.

Question. What are the harmful effects of air pollution?
Answer.
(i) Respiratory problems like sneezing, allergy, asthma or bronchitis in some persons.
(ii) Cause acid rain which leads to deterioration of metals and other building material.
(iii) Cause global warming which leads to change in the climate of the Earth.
(iv) Carbon monoxide may lead to many problems of respiratory system.
(v) Smog, which reduces the visibility as well as causes respiratory ailments.

Question. Draw labelled diagrams of (a) Carbon cycle (b) Oxygen cycle and briefly explain oxygen cycle.
Answer.
(a) Carbon cycle :

Carbon cycle is the cycle in which carbon is exchanged between the various sphere of Earth by taking many forms.
(b) Oxygen Cycle :

Oxygen from the atmosphere is used up in combustion, respiration and in the formation of oxides of nitrogen. Oxygen is returned to the atmosphere through photosynthesis. This
constitutes oxygen cycle in nature.

Question. (a) Where are ozone layer found?
(b) What is ozone hole and how is it caused?
(c) State the harmful effects of ozone depletion.
Answer.
(a) Ozone layer is found in stratosphere.
(b) Substances such as CFCs lower the ozone layer but do not directly destroy ozone. First they undergo photolysis, forming hydrogen chloride (HCl) or chlorine nitrate (ClNO₃), molecules that slowly decompose and give a small number of chlorine atoms (Cl) and chlorine monoxide (ClO) molecules that catalyze the destruction of ozone.
(c) The depletion of ozone layer may cause :
(i) Skin cancer
(ii) Damage to eyes
(iii) Damage to immune system
(iv) In plants also it may increase the harmful mutations.

Question. What is the chemical formula of ozone? What essential function does this gas perform and where it is found?What are CFCs?
Answer. O₃ is the chemical formula of ozone.
Essential function :
(i) It absorbs the harmful solar UV radiation to prevent various harmful effects on man, animals and plants.
(ii) Ozone is found in the stratosphere, i.e., about 18-50 km above the atmosphere.
(iii) CFCs (Chlorofluorocarbons) are synthetic harmful chemicals which are used in refrigerators and air conditioners as coolants, in fire extinguishers, in aerosol sprayers, etc. They are responsible for depletion of ozone layer in the atmosphere.

Question. State any four personal choices you would like to make to reduce energy consumption without affecting the quality of life or work explaining how each one of them would help you to do so.
Answer.
(i) By switching off unnecessary lights and f This will reduce consumption of coal in production of electricity.
(ii) By using public transport such as bus, metro, train, etc. as much as possible. This will reduce consumption of petrol and diesel.
(iii) By repairing leaked water taps. We can save water by following this method. This will save energy that is spent during treatment and pumping of water.
(iv) Reusing used paper, envelopes, etc. This will save the trees from which paper is made; it will also save energy spent on making and recycling papers.

Question. What are the harmful effects of modern farming practices? Mention any three effects.
Answer.
(i) Modern farming practices are based on excessive use of fertilizers and pesticides.
(ii) These are used to increase the crop production as well as for pest and weed control.
(iii) From the soil, these chemicals enter the food chain and affect the life of living organisms.
Harmful effects :
(i) The excessive use of fertilizers and pesticides affects the fertility of soil.
(ii) Harmful non-biodegradable chemicals enter the food chain and adversely affect the health of animals.
(iii) Excessive use of fertilizers and pesticides in the long run reduces the soil fertility.

Question. (a) Explain how forests influence the quality of our air, soil and water resources.
(b) State two ways in which atmospheric carbon dioxide is fixed.
Answer.
(a) Forests influence the quality of our air, soil and water resources in many ways :
(i) The vegetation/trees in the forest purify the air by the process of photosynthesis.
(ii) The roots of trees and plants bind the soil and prevent the soil erosion as well as floods.
(iii) The roots absorb the water present in the soil as groundwater.
(iv) The water released by the process of transpiration as water vapour becomes a part of atmosphere which helps to bring the rain.
(v) The forests also help to regulate the temperature of air.
(b) (i) Carbon dioxide is fixed into carbohydrate by the process of photosynthesis.
(ii) The carbon dioxide is fixed in the form of carbonates and bicarbonates; compounds and endoskeletons and exoskeletons of various animals are formed from carbonate salts.

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