Q.1. Define environment.
Ans. Environment is the sum total of all surroundings of a living organism, including the biotic and abiotic factors that influence each other.
Q.2. Give two examples of biotic elements.
Ans. Examples of biotic elements include air, land, water, etc.
Q.3. Name any two greenhouse gases.
Ans. Carbon dioxide and methane are greenhouse gases.
Q.4. What causes skin cancer in humans?
Ans. Exposure to ultraviolet (UV) radiation causes skin cancer in humans.
Q.5. Distinguish between renewable and non-renewable resources.
Ans. The following are the points of difference between renewable and non-renewable resources: omelette
(i) Renewable resources are those which can be used without the possibility of the resource becoming depleted or exhausted.
(ii) Examples: Trees, fish, water, etc.
(i) Non-renewable resources are those which get exhausted with extraction and use.
(ii) Examples: Petroleum, coal, iron-ore, etc.
Q.6. State some long-term impacts of global warming.
Ans. Some long-term impacts of global warming are:
(i) Melting of polar ice
(ii) Rise in sea level
(iii) Frequent coastal flooding and tropical storms
(iv) Disruption of drinking water supplies
(v) Extinction of species
(vi) Increased incidence of tropical diseases
Q.7. Why did ozone depletion take place?
Ans. Ozone depletion is the phenomenon of reductions in the amount of ozone in the stratosphere. The problem of ozone depletion has taken place due to high levels of chlorine and bromine compounds in the stratosphere. These compounds originate:
(i) in chlorofluorocarbons (CFC) − used as cooling substances in air conditioners and refrigerators; or
(ii) as aerosol propellants and bromofluorocarbons (halons) − used in fire extinguishers
Q.8. Name the important mineral reserves in India.
Ans. The important mineral reserves in India are bauxite, copper, chromate, diamonds, gold, lead, lignite, manganese, zinc, uranium, etc.
Q.9. List the major contributors to air pollution in urban India.
Ans. The major contributors to air pollution in urban India are:
(iii) Thermal power plants
Q.10. What are the major environmental concerns in India?
Ans. The major environmental concerns in India are:
(i) Land degradation
(ii) Biodiversity loss
(iii) Air pollution
(iv) Fresh water management
(v) Solid waste management
Q.11. Explain the factors responsible for land degradation.
Ans. The following factors are responsible for land degradation:
(i) High density of population and livestock - India supports around 17 per cent of the world’s human and 20 per cent of livestock population, while its geographical area is only 2.5 per cent of the total world’s area.
(ii) Various human activities such as forestry, agriculture, pastures, settlements and industries exert enormous pressure on the country’s limited land resources.
(iii) Deforestation takes place on a large scale to meet basic needs.
(iv) Soil erosion results in the loss of huge quantity of nutrients.
Q.12. Briefly explain
(i) Air pollution,
(ii) Water pollution and
(iii) Land pollution.
Ans. (i) Air Pollution: Carbon monoxide emitted by automobiles, smoke and other chemicals from manufacturing plants contribute to air pollution. The air pollution has created a hole in the Ozone layer leading to dangerous warming of the Earth.
(ii) Water Pollution: Water becomes polluted from dumping of waste and chemical by the industries established along the rivers. Water pollution is responsible for the death of aquatic animals and also poses threat to human life.
(iii) Land Pollution: Dumping toxic waste on land by heavy industries leads to land pollution. The quality of land is damaged and making it unfit for plantation or agricultural purpose. Restoring the quality of the land is a big problem.
Q.13. State the functions of the Pollution Control Boards.
Ans. The Pollution Control Boards (PCBs) perform the following functions:
(i) They investigate, collect and disseminate information relating to water, air and land pollution
(ii) They lay down standards for sewage/trade effluent and emissions.
(iii) These boards provide technical assistance to governments in promoting cleanliness of streams and wells.
(iv) The PCBs carry out and sponsor investigation and research relating to problems of water and air pollution.
(v) They organise a comprehensive mass awareness programme for the prevention and control of water and air pollution.
(vi) These boards prepare manuals, codes and guidelines relating to treatment and disposal of sewage and trade effluents.
Q.14. What are the human factors responsible for soil erosion in India?
Ans. The human factors responsible for soil erosion in India are:
(i) Deforestation: It is the removal of trees and other vegetation, which hold the soil together. When trees are removed, the soil surface becomes loose and hence, can be easily removed by running water and wind.
(ii) Overgrazing of Land: Grazing by animals removes grass over a large area, making it easy for running water and wind to remove the soil.
(iii) Improper Farming Techniques: Ploughing fields in the traditional up and down manner along the slopes makes it easier for running water and wind to cause soil erosion.
Q.15. Write two features of sustainable development.
Ans. Features of sustainable development are:
(i) It increases real per capita income and quality of life.
(ii) It helps in reducing pollution.
Q.16. How can solar energy be converted into electricity?
Ans. Solar energy can be converted into electricity with the help of photovoltaic cells.
Q.17. List any three traditional systems of medical treatment in India.
Ans. Ayurveda, Unani and Tibetan are the traditional systems of medical treatment in India.
Q.18. Explain the objectives of sustainable development.
Ans. The objectives of sustainable development are:
(i) Sustained Rise in Real per Capita Income and Quality of Life: The main objective of the sustained development is to maintain the remarkable level of real per capita income and the quality of life.
(ii) Reduction in Pollution: Sustainable development aims to discard those activities which prove to be detrimental to the natural resources and environment. Thus, reduction in the pollution at any cost is its main objective.
(iii) Rational Use of Natural Resources: Its means that people should avoid excessive or unnecessary exploitation of natural resources.
(iv) Fulfilling the Requirements of Future Generation: Sustainable development aims to minimise environmental problems and meet the needs of the present generation without compromising the ability of the future generation to meet their own needs.
Q.19. How does thermal power plant cause pollution?
Ans. Thermal power plant cause pollution in the following ways:
(i) Emission of large quantities of carbon dioxide, which is a greenhouse gas
(ii) Production of fly ash, which can cause land, air and water pollution, if not used properly
Q.20. How do animals help in biopest control?
Ans. Snakes prey upon rats, mice and various other pests. Similarly, birds such as owls and peacocks prey upon vermin and pests. If these are allowed to dwell around the agricultural areas, they can kill variety of pests, including insects. Lizards also help in reducing the insect population in the soil. It is important to know the value of these animals and save them.