Exercise : Solution of Questions on page Number : 258
Petroleum and coal are two fossil fuels.
Silviculture is the major programme started to replenish forests.
Apart from the availability of forest products, habitat of wild animals and soil conservation also get affected due to the destruction of forests.
(a) Tehri Dam: Bhagirathi river
(b) Sardar Sarovar Dam: Narmada river
(c) Bhakra Dam : Satluj river
Presence of coliform bacteria in the river water as well as the pH of the river can be used to find whether river water has been contaminated.
The presence of Coliform bacteria in water indicates the contamination with disease-causing micro-organisms.
Kulhs, Eris, Surangams, Kattas, Pynes are associated with rainwater harvesting.
(a) Coal is conserved when we save electricity.
(b) Petroleum is conserved when we use a bicycle for covering short distances instead of a motorbike.
The main purpose of rainwater harvesting is to save and conserve water for future use.
The name of the process in which the rainwater falling on the Earth is stopped from flowing and made to percolate into the ground is known as rainwater harvesting.
Rainwater harvesting is the most common practice of recharging ground water.
It means that river water is polluted with acidic wastes.
Amrita Devi Bishnoi is most remembered for the protection of Khejri trees in Rajasthan.
False. Chipko Andolan was associated with the conservation of trees.
(a) CFL: Compact Fluorescent Lamp
(b) CFC: Chlorofluorocarbon
Fossil fuels include all the other given terms, i.e. coal, natural gas and petroleum.
When we ‘reuse’ a product, we use the same thing without processing. Thus, it is better than the process of ‘recycling’.
Apart from LPG and natural gas, biogas is a clean gaseous fuel.
a) LPG is a fossil fuel but biogas is not a fossil fuel.
(b) Glaciers are a source of water.
(c) One of the main aim of management of forests and wildlife is to conserve the biodiversity, which we have inherited.
(d) Khadin is a traditional rainwater harvesting system in Rajasthan.
(e)When a fuel burns in an insufficient supply of air, then some poisonous gas called carbon monoxide is also produced.
Exercise : Solution of Questions on page Number : 259
“Sustainable development” is a kind of development that fulfils the basic needs of the present generation and also preserves the natural resources for the future generations.
Silviculture is the programme that aims to grow more trees and plants in order to replenish forests.
Following are the advantages of silviculture:
(a) It prevents flood and soil erosion.
(b) It maintains the water cycle.
(c) It helps in wildlife conservation by increasing the area of the earth under the forests.
(d) It provides different raw materials for industries.
‘Chipko Andolan’ was started by the common people to conserve the forests. The movement originated in a remote village named Reni, in Garhwal. In this movement, when the workers of a contractor came to cut the trees, in absence of the men of the village, all the women clasped the tree trunks in order to save the trees.
The forests and wildlife should be conserved in order to conserve our biodiversity, which we have inherited. The loss of forests and wildlife will result in the loss of forest ecosystem and ecological balance.
The ‘khadin’ system of rainwater harvesting practised in Rajasthan has a long earthen embankment known as bund, which is built across the edges of sloping farmlands. The rain water flows down the slope and is stopped by bund. It then forms a reservoir. The water in the reservoir seeps into the land and can be used for growing crops.
Electricity can be conserved in our houses using some measures. They are:
Switching off the electrical appliances when not needed
Using electrical efficient appliances like CFL.
Coal and petroleum are the fossil fuels and their supply is limited on the Earth. Therefore, we need to conserve them. They are made by the degradation of biomass, but this practise takes millions of years.
Yes, it is very important to conserve water as it is the basic necessity of all living beings. Humans, plants and animals, all need water for survival. But, the available water on the Earth is limited. Therefore, it should be conserved.
Carbon dioxide, sulphur dioxide, nitrogen oxide and water are produced by combustion of fossil fuels like coal and petroleum products. Their incomplete combustion produces carbon monoxide.
All of them, except water, are harmful for us and our environment. For example, sulphur oxide and nitrogen oxide, when mixed with water, cause acid rains. Increase in the carbon dioxide concentration in air causes greenhouse effect.
Coal and petroleum are fossil fuels that require millions of years to be formed. They are natural resources and are limited in supply. Once exhausted, they cannot be formed again in a short time. Therefore, fossil fuels like coal and petroleum should be used judiciously.
The three Rs are reduce, recycle and reuse.
The term ‘reduce’ aims at lowering the usage of natural resources to avoid wastage. For example, using less electricity.
The term ‘recycle’ aims at using the discarded items by recycling them. For example, recycling paper and plastic and sending them to the respective industries for the formation of new paper and plastic.
The term ‘reuse’ means using the same thing again and again. For example, using a paper bag over and over again.
Following are the main uses of coal and petroleum products:
Coal is used in homes and industries as a fuel. It is also used to generate electricity in power plants.
Petroleum products (such as petrol and diesel) are used as fuels in vehicles. Other products (like kerosene and LPG) are used as domestic fuels for cooking.
Coal is used to generate electricity and petroleum products are used as a fuel. The consumption of coal and petroleum products can be reduced in the following ways:
Use stairs instead of lift to save electricity.
Use bicycle to save fuel, like petrol.
Use solar cooker to save cooking fuel, like LPG.
Use public transport to save fuel.
Switch off lights, fans and other electrical appliances when not needed to save electricity.
Despite of good rains, we are not able to meet the demands for water of all the people in our country. This is because our population is increasing on a fast pace. Also, high yielding variety of crops require more water for irrigation, in urban areas people consume more water and the industrial waste and untreated sewage is discarded into rivers making it contaminated. All these things need large amount of water; hence, causing water scarcity.
Chipko Andolan shows how the participation of local people can lead to the efficient management of forests. It was started by the common people to conserve the forests. The movement originated in a remote village named Reni, in Garhwal. In this movement, when the workers of a contractor came to cut the trees in the absence of the men of the village, all the women clasped the tree trunks with their arms, in order to save the trees.
For rainwater harvesting from open spaces around the buildings in city areas, percolation pits are constructed and covered with concrete slabs having holes in it. They are connected to a recharge well via a pipe. The rain water goes into the percolation pit through the holes of the slab cover. It gets filtered in the pit and enters the recharge well via an outlet pipe and then, slowly, seeps into the soil.
(a) Natural resources are the things present in the environment that can be used by humans. Three important natural resources are water, fossil fuels, like coal and petroleum, and forest and wildlife.
(b) We need to manage our natural resources. The reasons for this are given below:
They are limited in amount. We need to manage them so that they can fulfil the need of the present as well that of the coming generations.
This will prevent their exploitation for short term gain.
This will ensure equal distribution of natural resources so that everyone can benefit from their development.
This will also minimise the damage to the environment, which is caused during the extraction and usage of natural resources.
(a) Following are the advantages of constructing dams across the rivers:
They can store excess water, thereby preventing floods.
Water from the dams can be used for the irrigation of crops via a network of canals.
After a suitable treatment, people of towns and cities get dam water through pipelines, for usage.
Water falling from the dams is used to generate electricity in hydropower plants.
(b) Following problems are associated with building dams:
Social problems: It makes many people homeless, by submerging large areas of human- settlements, thereby causing a social issue.
Environmental problems: It causes deforestation and loss of biodiversity by submerging large varieties of plants and animals. This creates an ecological imbalance.
Economic problems: This is an issue raised by many people who consider that construction of dams needs large amount of public money and there are no proportionate benefits.
(a) The sources of water other than rivers are rains, oceans, lakes, glaciers and wells.
(b) The water of river Ganga has been polluted by various human activities like bathing, washing of clothes, immersion of ashes of dead bodies and unburnt corpses in the river. The untreated sewage and industrial waste is also discarded in the river. Chemical effluents from the industries are also discharged in it. More than hundred towns and cities lie along its way, which discharge their waste in it. This has harmed the aquatic life of this river.
(a) The major industries that are based on forest produce are paper mills as well as industries dealing in timber, lac and sports equipment.
(b) The main aim of the management of forests and wildlife is to conserve our inherited biodiversity in order to maintain the ecological balance.
(c) The four main stakeholders in the management of forest resources are the people, the forest department, the industrialists and the forest and wildlife activists.
(a) Rainwater harvesting is the method of collecting rain water so that it can percolate in the soil more efficiently. The ancient structures used for rainwater harvesting by the rural people are Khadin in Rajasthan, Bandharas and Tals in Maharashtra, and Ahars in Bihar.
(b) Following are the various advantages of water stored under the ground:
It does not evaporate.
It spreads out to recharge wells and provides moisture to the crops.
It does not promote breeding of mosquitoes.
It is not contaminated by human and animal wastes.
It can be utilised by the local population.
(b) forests and wildlife
Amrita Devi Bishnoi, along with the Bishnoi community, worked for the protection of wildlife and forests.
The Chipko Andolan is associated with the conservation of trees. It was initiated to protect the trees from being cut.
(d) conservation of forests and wildlife
Amrita devi Bishnoi was associated with the conservation of forests and wildlife.
(d) the people who live in urban areas
People living in urban areas do not directly contribute in the management of forests. Thus, they are not the direct stakeholders.
(c) below 7
Acidic substances have less than 7 pH.
Exercise : Solution of Questions on page Number :260
Silviculture is the major programme that was started to replenish the damaged forests.
Amrita Devi Bishnoi is associated with the conservation and protection of khejrali trees.
(d) carbon monoxide
All other gases, except carbon monoxide, react with water to produce acid. Thus, they contribute to acid rain.
Carbon monoxide, i.e. CO, binds with red blood cells and reduces its oxygen carrying capacity.
Sargam is not an ancient harvesting structure.
(c) their skin is expensive
Snakes are killed for their skin, which is very expensive. Their skin is sold in markets.
Biogas does not require millions of years to form. Therefore, it is not a fossil fuel.
Electricity is a man-made resource.
Forests are being cut on a large scale. Therefore, they are the most rapidly dwindling natural resource in the world.
(c) wooden house
Wooden houses are made by man. Hence, it is not a natural resource.
(d) reduce, recycle, reuse
The three R’s, i.e. reduce, recycle, reuse, can help us to conserve natural resources for a long-term use.
(d) disposal of unburnt corpses into river water
The coliform bacteria is present in human intestine. Its presence shows contamination. The main reason for the presence of abundant coliform bacteria in river Ganga is the disposal of unburnt corpses into the river water.
(b) car battery manufacturing factory
Such factories produce acidic wastes that make the river water acidic.
(c) Sustainable development does not take into consideration the viewpoints of all stakeholders.
Sal trees dominate Arabari forest of Bengal.
(a) process of afforestation
Afforestation prevents the water from immediately rushing into the rivers. Due to this, water can seep in the ground and replenish the ground water.
(c) water harvesting
Ahars, Kattas, Bhundhis and Khadins are the ancient methods of water harvesting.
(c) wood, wind, sun
They all are natural resources, which are not fossil fuels.
(c) windmills for generating power
Windmills use wind to generate electric energy. They do not create any kind of pollution. Thus, they are eco-friendly.
(b) recharge groundwater
Khadins are used in Rajasthan to conserve water.
Exercise : Solution of Questions on page Number :261
(a) W refers to the fertilisers.
(b) X is Algae and Y is oxygen.
(c) The process Z is known as eutrophication.
(d) During the process of eutrophication (Z), when the alga (Y) dies, the bacteria present in the water decay the alga.
(e) This example shows that excessive use of fertilisers (W) is bad for the environment.
Organism A is a snake as it feeds on rats and it is being killed to make fancy items.
Organism B is a rat.
Organism C is the skin of a snake that is used in making fancy items.
Organism D is a cat as it also feeds on rats (B).
(a) (i) Fuel A is petroleum and (ii) fuel B is coal.
(b) (i) C is carbon dioxide, (ii) D is water, (iii) E is sulphur dioxide and (iv) F is nitrogen oxide.
(c) The process of formation of F during lightning is known as natural nitrogen fixation.
(d) Fuel A is supposed to be exhausted sooner.
(e) Fuel B, i.e. coal, is mostly used for generating electricity at thermal power plants.
(a) Device X is a solar cooker.
(b) Solar energy is the source of energy that cooks food in this device.
(c) Greenhouse effect is the process that traps energy in this device.
(d) The advantage of this technique is that it does not cause any pollution or harm to the environment.
(a) (i) P is a CFL (Compact Fluorescent Lamp), and (ii) Q is a filament type bulb.
(b) Filament is present in a bulb, not in CFL.
(c) Energy C is heat energy.
(d) P is more energy efficient.
(e) Coal will be conserved if all of us switch over to devices like P (CFL). This is because it is used in generating electricity.