Natural Resources: Definition and Important Questions

Important questions for CBSE Class 9 Science Natural Resources have been provided in the article. Natural resources are Earth-derived materials that are utilised to sustain life and fulfil human requirements. It might be any natural material that people utilise. Allocations of natural resources may be at the root or centre of many political & economical conflicts, both inside and between nations. 

This is especially true when there is a rise in scarcity and shortages. Extraction of natural resources is also a major cause of human rights abuses and environmental devastation. Natural resources can be categorised in a variety of ways. They are materials & components that can be discovered, naturally.

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Very Short Answer Questions [1 Mark Questions]

Ques. What is smog? [CCE 2012]

Ans. Smog is a mist that forms in cold weather due to the presence of unburned carbon particles, nitrogen oxides, or sulphur in the air with dark brown or greyish smoky. It suffocates and harms the eyes, nose, and lungs, in addition to harming various internal organs.

Ques. List any two harmful effects of smog.

Ans. The following are the Harmful Effects of smog.

• Allergy, asthma, bronchitis and suffocation in human beings & animals.
• Silvering, glazing & necrosis in plants.

Ques. Explain the formation of sea breeze in coastal areas. [CCE 2012]

Ans. During the day, it is the movement of a cooler wind from the sea to the land. Land heats up more quickly throughout the day. The air above the ground warms up, rises, and forms a low-pressure zone. Above the sea, the air is colder and has a greater pressure. It moves closer to the ground.

Ques. Explain the formation of land breezes in coastal areas.

Ans. Land cools swiftly at night, whereas seawater remains warmer. Warmer air rises over the sea, producing low pressure. Above the ground, the air is colder and has a higher pressure. It's heading for the sea.

Ques. “It is necessary to conserve natural resources.” Explain. [CCE 2012]

Ans. Natural resources (for example, air, water, soil, forests, minerals, and fossil fuels) are earth resources that humans use to satisfy their needs. However, due to their indiscriminate & excessive usage, these resources are already in limited supply, posing a threat to our well-being. As a result, there is a pressing need to conserve them by limiting their usage and taking steps to improve their supply.

Short Answer Questions [2 Marks Questions]

Ques. Describe how lichens and big trees influence the formation of soil.

Ans. Living Organisms: Chemicals are secreted by lichens in order to dissolve minerals from the rock surface. Dust gathers in crevices as a result of this. Mosses can be found there. They cause fissures to enlarge and minor fractures to appear. These gaps are widened by the roots of short-lived plants. Rock fragmentation is caused by the roots of bigger plants entering crevices and expanding in size.

Ques. How is smog formed? What does it indicate? [CCE 2012]

Ans. Smog is an opaque fog that forms when air is not circulated, resulting in the buildup of suspended particulate matter, toxic gases, hydrocarbons, and water vapours.

It signifies that the area has a high amount of pollution owing to industry and motor traffic.

Read Also: How are clouds formed?

Ques. Explain the role of the atmosphere in keeping climate control. [CCE 2012]

Ans. As a temperature buffer, the atmosphere aids in the maintenance of a region's climate by conserving heat across the area. Neither the daytime nor the nighttime temperatures are excessively hot or cold. As a result of the inclination of the land towards the sun, the average temperature of a place remains constant.

Ques. Write the composition of the soil. On what basis is the type of soil decided? [CCE 2014]

Ans. Soil Composition: Mineral matter accounts for 45% of soil, followed by organic matter (5%), air (25%), water (25%), and a variable amount of soil organisms. Gravel (size 2-10 mm), sand (0.02-2.0 mm), silt (0.002-0.02 mm), and clay make up mineral matter (below 0.002 mm) Humus is an organic substance that has deteriorated to a semi-decayed state.

Type of Soil: The average particle size of soil affects its textural structure, such as clayey, loam, or sandy. Mineral availability, soil moisture, and soil aeration are all determined by soil particles.

Ques. What are CFCs? Why are they harmful? [CCE 2013]

Ans. Chlorofluorocarbons (CFCs) have been used as aerosol propellants, refrigerants, shaving foams, foam sheets and mattresses, spray agents, and other applications. They enter the stratosphere and emit chlorine. Chlorine depletes the ozone layer and converts it to oxygen. As a result, the ozone layer in the stratosphere depletes, allowing dangerous UV rays to reach the planet.

Long Answer Questions [3 Marks Questions]

Ques. How are clouds formed and bring us rain? Explain briefly. [CCE 2012]

Ans. Wet air masses drift in the direction of the prevailing wind, forming clouds. They appear when a significant quantity of water vapours occurs. Due to the warmth of water bodies and moist regions throughout the day, evaporation occurs on their surfaces. Plants and animals both emit water vapours through transpiration. 

Plants do so through exhaled air and perspiration, while mammals do it through exhaled air and perspiration. During the day, the air warms up as well. The heated air rises, along with the water vapour. Air expands and cools as it rises in altitude. The water vapours condense as the temperature drops. Dust and other objects suspended in the air serve as nuclei around which water vapour condenses. Clouds arise when a huge amount of moist air condenses.

Clouds travel in the same direction as the wind. Further condensation of water droplets changes the same into rain when they encounter chilly air or high mountains.

Read More: What is Groundwater?

Ques. What is meant by air pollution? Explain any three human activities that cause air pollution. Mention any two harmful effects of air pollution. [CCE 2014]

Ans. Air pollution is defined as the introduction of particulate particles, gases, & vapours into the environment atmosphere that harm humans, animals, flora, & human assets.

Three human activities that contribute to air pollution are:

1. Fossil fuels are burned in industry, cars, and power plants.
2. Textiles, asbestos, and wheat processing industries are examples of processing industries.
3. Crushing of stones.

Harmful Effects: 

• Effect on Animal Life: Respiratory problems, eye and throat irritation, allergies, haemorrhages, decreased appetite, frequent diarrhoea & bone thinning are all effects on animal life.
• Effect on Plant Life: Chlorosis, water-saturated regions, necrosis, dieback & defoliation are all effects on plant life.

Ques. (a) The circulation of carbon is important in nature. Give reasons for your answer.

(b) Explain any two processes involved in the cycling of nitrogen in the environment. [CCE 2011, 2012]

Ans. (a) All organic compounds require carbon as a component. Its concentration in the atmosphere, however, is quite low. As a result, carbon circulation is critical for the survival of life on Earth. During the photosynthesis process, CO₂ is converted into organic compounds. Plants transfer the organic matter to animals, who pass it on to animals, who pass it on to decomposers. It is absorbed on a regular basis by all living things, releasing CO₂. CO₂ is also emitted when organic stuff decomposes.

(b) The following are the processes that involve in the Nitrogen cycle.

1. Nitrogen fixation
2. Nitrogen assimilation
3. Decomposition involving ammonification & nitrification
4. Denitrification

Nitrogen Fixation: Nitrogen fixation is the process of extracting nitrogen from the atmosphere in its molecular form (N₂) and converting it into nitrogen compounds that may be used in other biological processes. Fixation can take place in the atmosphere (lightning), in industry, or in biology.

Denitrification: The loss of nitrogen compounds in particular: bacterial reduction of nitrates or nitrites (as in soil), which generally results in nitrogen escaping into the air.

Read Also: Role of Atmosphere in Climate Control

Ques. Many human activities lead to increasing levels of pollution of air, water bodies and soil. “Isolating these activities to specific and limited areas would not help in reducing pollution.” Justify the statement by giving at least five reasons. [CCE 2011, 2012]

Ans. It is frequently advised that all polluting units be asked to relocate outside of the city borders so that the residential area is not adversely affected. This, however, is of little use since

1. Acid rain is caused by the burning of fossil fuels, which spreads over broad distances, destroying plants, polluting water bodies, and harming humans and their assets.
2. Greenhouse gases are released into the environment by polluting units. They contribute to global warming.
3. A variety of air contaminants enter the stratosphere, causing the protective ozone layer to deplete.
4. When sewage is discharged into bodies of water, the water becomes unsafe for eating since it becomes a source of a variety of water-borne illnesses. Scum, a nasty odour, and a poor taste abound.
5. Many harmful chemicals and heavy metals slowly trickle down and combine with groundwater when industrial effluents are dumped over the land.

Very Long Answer Questions [5 Marks Questions]

Ques. (a) Why is the atmosphere essential for life?

(b) Explain how the atmosphere acts as a blanket? [C.C.E. 2014]

Ans. (a) Due to the following reason, the atmosphere is essential for life.

1. Oxygen: The atmosphere includes oxygen, which is required for most species' combustion & respiration.
2. Carbon Dioxide: The atmosphere supplies carbon dioxide or CO₂ to plants which helps in the process of photosynthesis.
3. Protection: Cosmic rays & high-energy UV rays are filtered off by the atmosphere.
4. Temperature Buffer: The atmosphere prevents daytime temperatures from rising too high or nighttime temperatures from falling too low. This maintains a comfortable temperature for live creatures.
5. Other Functions: Air currents also aid in the spread of spores and other dissembles. The water cycle occurs in the atmosphere and results in rain, which replenishes fresh water on land.

(b) The atmosphere, or air, is a poor heat conductor. As a result, it serves as a blanket.

1. It doesn't allow for a rapid rise in temperature throughout the day while the sun is shining overhead.
2. During the night, there is no rapid cooling. The atmosphere hinders the escape of heat from the portion of the planet that is dark to outer space.
3. The atmosphere keeps the earth's average temperature relatively constant throughout the year, not only during the day.

Ques. “Urbanisation and industrialisation are mainly responsible for an increase in environmental pollution”. Justify this statement and suggest ways and means check it. [CCE 2012]

Ans. Urbanisation & industrialisation generate a lot of pollutants:

1. Sewage: In metropolitan places, a lot of sewage is produced. It's full of organic stuff as well as germs.
2. Industrial Effluents: Most industries, such as electroplating units, paper mills, dyeing units, leather processing units, chemical companies, sugar mills, and so on, manufacture them. Industrial effluents, like sewage, are disposed of by flowing into a water body.
3. Fossil Fuels: SPM, pollutant gases, and hydrocarbon vapours are produced by the combustion of fossil fuels in homes, factories, autos, and thermal plants.
4. Processing Industries: Cotton dust, iron dust, coal dust, asbestos, and other polluting particle matter are produced.
5. Garbage and Trash: They're garbage from both residential and business regions.

Control

1. Sewage Treatment: It eliminates the majority of organic materials while also killing microorganisms.
2. Effluent Treatment: It eliminates harmful substances.
3. Garbage: It may be used to generate biogas & manure as well as produce manure.
4. Trash: It is recycled in part & thrown in the garbage in part.
5. Electrostatic Precipitators: They clear the air of suspended particles.
6. CNG: Automobile pollution is reduced when CNG is used in vehicles.

Read Also: Air Pollution

Ques. (a) Describe the role of photosynthesis and respiration in the carbon cycle.

(b) What is meant by the biogeochemical cycle? Name two essentials that are transferred between different components of the biosphere. [CCE 2011]

Ans. (a) (i) Photosynthesis: It absorbs CO₂ and converts it into organic food like glucose, carbohydrates, proteins, and lipids. Organic food is transmitted from producers to herbivores, who then pass it on to predators in the ecosystem.

(ii) Respiration: It releases energy for bodily functions by oxidising glucose and other chemical molecules. CO₂ is released into the atmosphere.

(b) Biogeochemical Cycle: Biogeochemical cycling is the recurrent circulation of biogeochemical or biogenetic nutrients between abiotic & biotic components of the environment, such as the CO₂ cycle, N₂ cycle, Water cycle, & O₂ cycle.

Biogeochemical & Energy: Biogeochemical are absorbed by plants and converted into organic matter, which includes chemical energy as part of the photosynthesis process. The biogeochemical & energy inherent in organic food flow from plants to creatures that eat plants. Other animals eat the animals that eat the animals that eat the animals that eat the animals that absorb the biogeochemical and energy inherent in biological stuff. The higher trophic levels, on the other hand, do not receive all of the energy. Every time energy is transferred, it is dissipated. Decomposers act on organic wastes and dead bodies of all species to release biogeochemical into the abiotic environment.

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