NCERT Exemplar Class 10 Science Solutions Chapter 16 Management of Natural Resources

Question:2

The most rapidly dwindling natural resource in the world is
(a) water
(b) forests
(c) wind
(d) sunlight
Answer:(b)
Forests are the most quickly diminishing natural resource on the planet. They are crushed aimlessly as they give crude material to different businesses, for example, wood industry, paper industry, sports industry, and so on

Question:3

The most appropriate definition of a natural resource is that it is a substance/commodity that is:
(a) present only on land
(b) a gift of nature which is very useful to mankind
(c) a man-made substance placed in nature
(d) available only in the forest
Answer:(b)
Natural resources occur naturally within an environment that exists relatively undisturbed by a humans, in a natural form. A ‘natural resource’ is a substance/commodity of nature which is very useful to mankind. These are air, water, soil, etc.
(a) These can be present anywhere, not necessarily only on land.
(b) These are a gift of nature that is very useful to mankind.
(c) These are not man-made substances.
(d) These can be present anywhere, not necessarily only in the forest
Hence, option (b) is correct.

Question:4

The main cause for abundant coliform bacteria in the river Ganga is
(a) Disposal of unburnt corpses into water
(b) Discharge of effluents from electroplating industries
(c) washing of clothes
(d) Immersing ashes
Answer:(a)
The fundamental cause for abundant coliform bacteria in the river Ganga is disposal of unburnt corpses into water. Coliform are the gathering of microbes discovered in human digestive organs whose presence in water demonstrates contamination by disease-causing microorganisms.
Hence, option (a) is correct.

Question:5

The pH of water sample collected from a river was found to be acidic in the range of 3.5 – 4.5, on the banks of the river were several factories that were discharging effluents into the river. The effluents of which one of the following factories is the most likely cause for lowering the pH of river water?
(a) Soap and detergent factory
(b) Lead battery manufacturing factory
(c) Plastic cup manufacturing factory
(d) Alcohol distillery
Answer:(b)
Lead is a significant constituent of lead-acid battery utilized widely in vehicle batteries. The release of lead from battery fabricating processing plants can bring down the pH of river water.
Soap is a combination of a weak acid and a strong base, which results in a salt that is basic on the pH scale. It does not lower the pH of river water.
Similarly, Plastic cup manufacturing factories and Alcohol distilleries does not lower the pH of river water
Hence, option (b) is correct.

Question:6

The pH range most conducive for life of fresh water plants and animals is
(a) 6.5 – 7.5
(b) 2.0 – 3.5
(c) 3.5 – 5.0
(d) 9.0 – 10.5
Answer:(a)
The pH of the water body should be in the range of 6.5-7.5 for the survival of freshwater plants and animals. Below and above this range is harmful to aquatic life.
Hence, option (a) is correct.

Question:7

The three R’s that will help us to conserve natural resources for long term use are
(a) recycle, regenerate, reuse
(b) reduce, regenerate, reuse
(c) reduce, reuse, redistribute
(d) Reduce, recycle, reuse
Answer:(d)
The three R's that help us to conserve natural resources for long term use are reduced, recycle, reuse.
Reduce: This means less use of natural resources, e.g., save water by repairing leaky taps.
Recycle: This means a collection of materials like plastic, paper, glass etc., to make required things instead of synthesizing or extracting fresh plastic, paper, glass etc.
Reuse: Instead of throwing articles (e.g., used envelopes) use them again. This is better than recycling because the recycling process uses some energy.
Hence, option (d) is correct.

Question:8

Given below are a few statements related to biodiversity. Pick those that correctly describes the concept of biodiversity
(i) Biodiversity refers to the different species of flora and fauna present in an area
(ii) Biodiversity refers to only the flora of a given area
(iii) Biodiversity is greater in a forest
(iv) Biodiversity refers to the total number of individuals of a particular species living in an area
(a) (i) and (ii)
(b) (ii) and (iv)
(c) (i) and (iii)
(d) (ii) and (iii)
Answer: (c)
Biodiversity refers to the different species of flora and fauna present in an area. Hence, statement (i) is correct, and statement (ii) is incorrect.
It is greater in a forest due to the availability of plenty of resources. Hence, statement (iii) is correct.
The total number of individuals of a particular species living in an area is represented as population and not biodiversity. Hence, statement (iv) is incorrect.
Hence, option (c) is correct.

Question:9

Among the statements given below select the ones that correctly describe the concept of sustainable development
(i) Planned growth with minimum damage to the environment
(ii) Growth irrespective of the extent of damage caused to the environment
(iii) Stopping all developmental work to conserve the environment
(iv) Growth that is acceptable to all the stakeholders
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) (iii) only
Answer:(a)
Sustainable development implies arranged development/planned growth with least harm to the climate. The growth of environment should not be harmful to the partners too. It ought to be worthy to them, e.g., if some trees have to be cut for different purposes, then harm/damage to the environment can be minimized by planting new samplings instead of cut trees.
Hence, option (a) is correct.

Question:10

In our country, vast tracts of forests are cleared and a single species of plant is cultivated. This practice promotes
(a) biodiversity in the area
(b) Monoculture in the area
(c) growth of natural forest
(d) Preserves the natural ecosystem in the area
Answer:(b)
The practice of clearing vast tracts of forests and cultivating a single species of plant is known as monoculture. This devastates the biodiversity in the region as the number of species lowers. It likewise upsets or disturbs the natural ecosystem in the area. Hence, it decelerates the growth of the natural forest.
Hence, option (b) is correct.

Question:11

A successful forest conservation strategy should involve
(a) Protection of animals at the highest trophic level
(b) Protection of only consumers
(c) Protection of only herbivores
(d) Comprehensive programme to protect all the physical and biological components
Answer:(d)
Forest conservation strategy should involve exhaustive projects to ensure all the physical and biological components, (i.e., the ecosystem). In the event that living beings just at a specific trophic level are protected, the ecosystem would be disturbed, as the organisms at the lower trophic level would disappear quickly.
This will prompt circumstances where the organisms at all the upper trophic levels would die due to starvation.
Hence, option (d) is correct.

Question:12

The important message conveyed by the ‘Chipko Movement’ is
(a) to involve the community in forest conservation efforts
(b) to ignore the community in forest conservation efforts
(c) to cut down forest trees for developmental activities
(d) government agencies have the unquestionable right to order the destruction of trees in forests
Answer:(a)
The Chipko movement was a non-violent agitation in 1973 that was aimed at the protection and conservation of trees. The important message conveyed by the ‘Chipko Movement' was to involve the community in forest conservation efforts.
People’s participation can help in increasing forest as well as help in their conservation.
Hence, option (a) is correct.

Question:13

In our country, there are attempts to increase the height of several existing dams like Tehri and Almati, dams across Narmada. Choose the correct statements among the following that are a consequence of raising the height of dams
(i) Terrestrial flora and fauna of the area is destroyed completely
(ii) Dislocation of people and domestic animals living in the area
(iii) Valuable agricultural land may be permanently lost
(iv) It will generate permanent employment for people
(a) (i) and (ii)
(b) (i), (ii) and (iii)
(c) (ii) and (iv)
(d) (i), (iii) and (iv)
Answer:(b)
The consequences of raising the height of dams are as follows:

• The terrestrial flora and fauna of the area are destroyed completely.

• It leads to deforestation and loss of biological diversity.

• It also leads to the dislocation of people and domestic animals living in an area, which causes various social problems. Significant farming areas might be forever lost.

• The people are not even given adequate compensation for their losses. This obviously leads to economic problems such as temporary unemployment for people.

Hence statements (i), (ii), and (iii) are correct.
Hence, option (b) is correct.

Question:14

Expand the abbreviation GAP
(a) Governmental Agency for Pollution Control
(b) Gross Assimilation by Photosynthesis
(c) Ganga Action Plan
(d) Governmental Agency for Animal Protection
Answer:(c)
GAP stands for the Ganga Action Plan.
The Ganga action plan was launched by Shri Rajeev Gandhi on 14 Jan 1986.
The main objectives were:

• 1. Pollution abatement

• 2. Improve the water quality by Interception, Diversion and treatment of domestic sewage

• 3. Prevent toxic and industrial chemical wastes from polluting and entering in to the river.

Question:15

Select the incorrect statement
(a) Economic development is linked to environmental conservation
(b) Sustainable development encourages development for the current generation and the conservation of resources for future generations
(c) Sustainable development does not consider the viewpoints of stakeholders
(d) Sustainable development is a long-planned and persistent development
Answer:(c)
Sustainable development thinks about the perspectives of partners or the stakeholders.
It is a cycle wherein decentralized economic growth and ecological protection go inseparably. It empowers advancement for current generation and the preservation of resources for future generation as well.
It is a long-planned and persistent development. Today, financial development is connected to environmental protection. The climate isn't degraded or put to hazard for the sake of a monetary turn of events.
Hence, statement (c) is incorrect and thus the correct answer.

Question:16

Which of the following is not a natural resource?
(a) Mango tree
(b) Snake
(c) Wind
(d) Wooden house
Answer:(d)
Natural resources occur naturally within an environment that exists relatively undisturbed by a humans, in a natural form.
Wood is not a natural resource. It is man-made.
A mango tree, snake and wind are natural resources. They are present in the environment naturally.
Hence, option (b) is correct.

Question:17

Select the wrong statement
(a) Forests provide a variety of products
(b) Forests have greater plant diversity
(c) Forests do not conserve soil
(d) Forests conserve water
Answer:(c)
Forests are major sites for conservation of soil. The roots of trees firmly hold the soil particles to protect it from flowing away. The humus is more in the soil of forests.
Forest provides variety of products, e.g., timber, paper etc. They have a greater plant diversity as different type of plants are naturally present. Forest also helps in conservation of water.
Hence, option (c) is correct.

Question:18

Arabari forests of Bengal is dominated by
(a) Teak
(b) Sal
(c) Bamboo
(d) Mangroove
Answer:(b)
Arabari forests of Bengal is dominated by sal trees.
With the dynamic and willing support of the local community, these forests went through an astounding recovery by 1983.
Hence, option (b) is correct.

Question:19

Ground water will not be depleted due to
(a) Afforestation
(b) Thermal power plants
(c) Loss of forest and decreased rainfall
(d) Cropping of high water-demanding crops
Answer:(a)
Afforestation means plantation of trees. Groundwater will not be depleted due to afforestation.
Thermal power plants pollute the groundwater.
Loss of forest and decreased rainfall also pollute the groundwater.
Most of the groundwater is polluted due to the use of excess water for the cropping of high water-demanding crops.
Hence, option (a) is correct.

Question:20

Opposition to the construction of large dams is due to
(a) social reasons
(b) economic reasons
(c) enviromental reasons
(d) All of the above
Answer:(d)
Opposition to the construction of large dams by local people is due to social, economic and environmental problems.
The consequences of raising the height of dams are as follows:

• Environmental: The Terrestrial flora and fauna of the area are destroyed completely. It leads to deforestation and loss of biological diversity.

• Social: It leads to the dislocation of people and domestic animals living in an area, which causes various social problems. Significant farming areas might be forever lost.

• Economic: The people are not even given adequate compensation for their losses. This obviously leads to economic problems such as temporary unemployment for people.

Hence, option (d) is correct.

Question:21

Khadins, Bundhis, Ahars and Kattas are ancient structures that are examples for
(a) grain storage
(b) wood storage
(c) water harvesting
(d) soil conservation
Answer:(c)

• Khadin is an ingenious construction designed to harvest surface runoff water for agriculture. These are mostly found in Rajasthan.

• Bundhis are used for water harvesting in Madhya Pradesh and Uttar Pradesh.

• Ahars are reservoirs with an embankment on three sides mostly found in Bihar.

• Kattas are temporary check dams built across streams and rivulets found in Karnataka.

All these are still in use today for the conservation of water.
Hence, option (c) is correct.

Question:22

Pick the right combination of terms which has no fossil fuel.
(a) Wind, ocean and coal
(b) Kerosene, wind and tide
(c) Wind, wood, sun
(d) Petroleum, wood, sun
Answer:(c)
Fossil fuel is a general term for buried combustible geologic deposits of natural materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years.
Wind, wood, and sun have no fossil fuel.
Coal, petroleum and kerosene are fossil fuels in the given list
Hence, option (c) is correct.

Question:23

Select the eco-friendly activity among the following
(a) Using car for transportation
(b) Using polybags for shopping
(c) Using dyes for colouring clothes
(d) Using windmills to generate power for irrigation
Answer:(d)

• Eco-friendly means earth-friendly or not harmful to the environment.

• The car uses petrol or diesel that is non-renewable. So it is not eco friendly

• Polybags are non-biodegradable. It is also not eco friendly

• Dyes are synthetic chemical compounds, so they are not eco friendly

• The wind is a renewable source of energy. So, using windmills to generate power for irrigation is an eco-friendly activity.

Hence, option (d) is correct.

Question:24

It is important to make small check dams across the flooded gullies because they
(i) hold water for irrigation
(ii) hold water and prevent soil erosion
(iii) recharge ground water
(iv) hold water permanently
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (ii) and (iv)
Answer:(b)
It is important to make small check dams across the flooded gullies because they recharge groundwater.
These small dams assist in withholding water. This gives dampness to the vegetation cover, subsequently preventing soil erosion.
Therefore, statements (ii) and (iii) are correct.
Hence, option (b) is correct.

Question:26

List two advantages associated with water harvesting at the community level.
Answer:

Water harvesting is a strategy for holding water on the outside of the earth to make it permeate under the ground in order to recharge groundwater.
Two advantages associated with water harvesting at the community level are:
(i) Giving people control or command over their local water resources guarantees that mismanagement is decreased to a minimum level.
(ii) The water stored in the ground does not evaporate, gives moisture for vegetation over a wide territory, and is protected from pollution by human and animal waste. Hence, over-exploitation of these resources is reduced.

Question:27

In a village in Karnataka, people started cultivating crops all around a lake which was always filled with water. They added fertilisers to their field in order to enhance the yield. Soon, they discovered that the waterbody was completely covered with green floating plants, and fishes started dying in large numbers.
Analyse the situation and give reasons for the excessive growth of plants and death of fish in the lake.
Answer:
Fertilizers mainly contain phosphates and nitrates. Using these fertilizers around the lake, makes the water body enriched with these chemicals.
This enhances the supplements in water, leading to excessive development of small, green, aquatic plants and the surface of water gets completely covered with plants. This process is called eutrophication. It induces excessive growth of algae.
These small plants consume most of the dissolved oxygen of the water, leading to its deficiency. Due to this, the fishes and the other aquatic life in the lake die because of oxygen starvation and depletion of light.

Question:28

What measures would you take to conserve electricity in your house?
Answer:

A few measures can be taken to conserve electricity in our house are as follows:

• (i) Turn off unnecessary lights

• (ii) Turn off the fans in unoccupied rooms and also when they are not required.

• (iii) Try to use natural light as much as possible. Maximize the use of solar radiation.

• (iv) Unplug unused electronics.

• (v) During winters, use solar water heating system instead of electric heaters.

• (vi) Fluorescent tubes or CFL should be used instead of electric bulbs as they consume less electricity.

Question:29

Although coal and petroleum are produced by degradation of biomass, yet we need to conserve them. Why?
Answer:

Coal and petroleum are formed from the degradation of biomass. This biomass included ancient plant life which lived millions of years ago.
These resources are being utilized at a much faster rate than they are being formed. So they will be exhausted in the near future. And then we would need to look for alternative sources of energy.
This is the reason why we need to conserve them, although these resources are produced by the degradation of biomass.

Question:30

Suggest a few measures for controlling carbon dioxide levels in the atmosphere.
Answer:

(i) Photosynthesis: It removes carbon dioxide naturally. Growing, reestablishing and managing forests to energize more carbon take-up can use the power of photosynthesis, changing a noticeable amount of carbon dioxide all around into carbon put away in wood and soils.
(ii) Reducing the consumption of petroleum in automobiles: This can be done using car-pools, public transport, electric bikes and other electric transport.
(iii) Use of alternative fuels such as CNG (clean fuel) instead of coal and petroleum
(iv) Prepare manure out of litter instead of burning it.
(v) The smoke emerging from the thermal power stations and different industries ought to be very much treated to eliminate harmful gases, prior to releasing it into the atmosphere.

Question:31

(a) Locate and name the water reservoirs in Figures 16.1 (a) and (b).
(b) Which has an advantage over the other and why?

Answer:
(a) The water reservoir is a pond in fig. (a) and an underground water body in fig. (b); i.e., the underground water body has more advantages over a water reservoir.
(b) There are many advantages of water stored in the ground. Some of these are as follows:

• (i) It does not evaporate.

• (ii) It spreads out to recharge wells and provides moisture for crops over a wide area.

• (iii) Stagnant water collected in ponds promotes the breeding of mosquitoes. Whereas water stored in the ground does not.

• (iv) Water stored in the ground is free from contamination by human and animal wastes.

• (v) It is utilized for the benefits of the local population

Question:33

Prepare a list of five activities that you perform daily in which natural resources can be conserved or energy utilisation can be minimised.
Answer:
Activities that we perform daily in which natural resources can be conserved or energy utilization can be minimized are as follows:
(i) Use fan and light only when required. Switch them off in unoccupied rooms.
(ii) Use CFL in place of conventional bulbs/tubes.
(iii) Avoid using a hose pipe for watering plants as a lot of water is wasted through it.
(iv) Turn off tap water when not in use.
(v) Use solar energy/natural light whenever possible.
(vi) Unused water in the water bottles may be used for watering plants.
(vii) Use public transport or car pools to save fuel.
(vii) Use CNG as an alternative fuel.
(ix) Pressure cookers should be used for cooking food to save fuel.
(x) Use the stairs to climb instead of taking the lift.

Question:34

Is water conservation necessary? Give reasons.
Answer:

Conservation of water is necessary due to the following reasons:
(i) Uneven distribution: Some parts of our country have high resources of water whereas other parts suffer from chronic water shortage. This causes floods in some regions and drought in other regions.
(ii) Fluctuation in rainfall is very common, and wide seasonal rains are observed yearly.
(iii) Dumping of untreated sewage and industrial wastes in rivers and ponds makes them polluted.
(iv) The changing lifestyle of people increases the consumption of water, especially in urban areas.
(v) High yielding varieties of crop uses much more water for irrigation.

Question:35

Suggest a few useful ways of utilising waste water.
Answer:

Some useful ways of utilizing wastewater are as follows
(i) Recharging the groundwater.
(ii) It can be used for agricultural purposes such as irrigation.
(iii) Treated water can be used for washing cars, watering gardens etc.
(iv) Recycling aquarium water
(v) Collect rainwater.
(vi) Wastewater from the kitchen can be collected and reused in toilet cleaning.
(vii) Certain pollutants in municipal water can act as fertilizer for various crops.

Question:36

What is the importance of forest as a resource?
Answer:

Forests are renewable natural resources. They are important as a resource due to the following reasons:
(i) They provide habitat, food and protection to wildlife.
(ii) Help in balancing CO₂ and O₂ of the atmosphere.
(iii) Improves water holding capacity of the soil.
(iv) It regulates the water cycle.
(v) For human beings, they are the source of various essential commodities like fuel, wood, timber, fruits, resins, etc
(vi) Forest helps in the conservation of biodiversity as a large number of species (of plants and animals) live inside them.

Question:37

Why are the Arabari forests of Bengal known to be a good example of conserved forest?
Answer:

Arabari Forest Range is the name of a forest range in West Bengal. The Arabari forest of Bengal was badly degraded. Conservation efforts were begun in 1972.
The West Bengal Forest Department (headed by Indian Forest Service officer Shri Ajit Kumar Banerjee) planned to revive the degraded forest by involving the local people.
The residents of the surrounding area were associated with the protection of 1272 hectares of this forest. With the dynamic participation of neighbourhood individuals living around the forest, the degraded sal forest of Arabari turned out to be thick and green within ten years.
Consequently, the residents were given work in both silviculture and harvesting operations of the forest and were permitted to gather firewood and fodder from the forest area on a very nominal payment. Thus, the Arabari forest provides a genuine example of a conserved forest.