Case Study Questions Class 12 Biology Chapter 16 Environmental Issues
CBSE Class 12 Case Study Questions Biology Environmental Issues. Term 2 Important Case Study Questions for Class 12 Board Exam Students. Here we have arranged some Important Case Base Questions for students who are searching for Paragraph Based Questions Environmental Issues.
At Case Study Questions there will given a Paragraph. In where some Important Questions will made on that respective Case Based Study. There will various types of marks will given 1 marks, 2 marks, 3 marks, 4 marks.
CBSE Case Study Questions Class 12 Biology Environmental Issues
Case study 1
Human population size has grown enormously over the last hundred years. This means increase in demand for food, water, home, electricity, roads, automobiles and numerous other commodities. These demands are exerting tremendous pressure on our natural resources, and are also contributing to pollution of air, water and soil. The need of the hour is to check the degradation and depletion of our precious natural resources and pollution without halting the process of development. Pollution is any undesirable change in physical, chemical or biological characteristics of air, land, water or soil. Agents that bring about such an undesirable change are called as pollutants.
In order to control environmental pollution, the Government of India has passed the Environment (Protection) Act, 1986 to protect and improve the quality of our environment (air, water and soil).
Que. 1) Undesirable changes which occurs in physical, biological and chemical characteristics are known as ………………………………………………………………………………………….
(a) Pollutants
(b) Pollution
(c) Protection
(d) Halting
Que. 2) The “Environment (Protection) act was passed by the government in ……………………………………………………………………………….
(a) 1996
(b) 1946
(c) 1956
(d) 1986
Que. 3) The agents which are responsible for causing undesirable changes such as chemical, physical or biological, these agents are known as …………………………………………………………………………..
(a) Pollutant
(b) Resistant
(c) Insects
(d) Depletion
Que. 4) What has been increased due to increased human population?
Que. 5) Which act was passed by the government to protect and improve quality of an environment?
Answer Key
Que. 1)(b) Pollution.
Que. 2) (d) 1986.
Que. 3) (a) Pollutant.
Que. 4) Answer: Demand for water, home, automobiles, food, and roads has been increase d due to increased human population.
Que. 5) Answer: Environment (Protect) act was passed by the government in the 1986 to protect and improve quality of an environment.
Case study 2
We are dependent on air for our respiratory needs. Air pollutants cause injury to all living organisms. They reduce growth and yield of crops and cause premature death of plants. Air pollutants also deleteriously affect the respiratory system of humans and of animals. Harmfuleffects depend on the concentration of pollutants, duration of exposure and the organism. Smokestacks of thermal power plants, smelters and other industries release particulate and gaseous air pollutants together with harmless gases, such as nitrogen, oxygen, etc. These pollutants must be separated/ filtered out before releasing the harmless gases into the atmosphere.There are several ways of removing particulate matter; the most widely used of which is the electrostatic precipitator, which can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant. It has electrode wires that are maintained at several thousand volts, which produce a corona that releases electrons.
These electrons attach to dust particles giving them a net negative charge. The collecting plates are grounded and attract the charged dust particles. The velocity of air between the plates must be low enough to allow the dust to fall. A scrubber can remove gases like sulphur dioxide.
Que. 1) Harmful effects of the air pollution mainly depends on the …………………………………………………………………………….
(a) Concentration of oxygen
(b) Concentration of pollutants
(c) Concentration calcium
(d) Concentration of Carbon dioxide
Que. 2) Which of the following releases pollutants with the harmless gases?
(a) Thermal power plant
(b) Industries
(c) Smelters
(d) All of them
Que. 3) In the electrostatic precipitator, corona releases electrons which attach to the dust particles and the electrons give ………………………………………………………………………………… charge to the dust particle.
(a) Net positive
(b) Net neutral
(c) Net negative
(d) No charge
Que. 4) Why air pollutants are harmful.
Que. 5) Name any two precipitator which can remove particulate matter.
Answer Key
Que. 1)(b) Concentration of pollutants.
Que. 2) (d) All of them.
Que. 3) (c) Net negative.
Que. 4) Answer: The air pollutants reduce growth of crops and yield of crops. It also causes injury to the respiratory system of all humans and animals. Hence, air pollutants are harmful.
Que. 5) Answer: Both electrostatic precipitator and scrubber can be used to remove harmful particulate matter.
Case study 3
With its very large population of vehicular traffic, Delhi leads the country in its levels of air-pollution – it has more cars than the states of Gujarat and West Bengal put together. In the 1990s, Delhi ranked fourth among the 41 most polluted cities of the world. Air pollution problems in Delhi became so serious that a public interest litigation (PIL) was filed in the Supreme Court of India. After being censured very strongly by the Supreme Court, under its directives, the government was asked to take, within a specified time period, appropriate measures, including switching over the entire fleet of public transport, i.e., buses, from diesel to compressed natural gas (CNG). All the buses of Delhi were converted to run on CNG by the end of 2002. You may ask the question as to why CNG is better than diesel. The answer is thatCNG burns most efficiently, unlike petrol or diesel, in the automobiles and very little of it is left unburnt. Moreover, CNG is cheaper than petrol or diesel, cannot be siphoned off by thieves and adulterated like petrol or diesel.
The main problem with switching over to CNG is the difficulty of laying down pipelines to deliver CNG through distribution points/ pumps and ensuring uninterrupted supply. Simultaneously parallel steps taken in Delhi for reducing vehicular pollution include phasing out of old vehicles, use of unleaded petrol, use of low-sulphur petrol and diesel, use of catalytic converters in vehicles, application of stringent pollution-level norms for vehicles, etc.
Que. 1) Which city has been ranked fourth in the most polluted cities?
(a) Kolhapur
(b) Nashik
(c) Pune
(d) Delhi
Que. 2) By the end of 2002, buses of Delhi were converted to run on ………………………………………………………………………………………….
(a) Petrol
(b) CNG
(c) Diesel
(d) All of them
Que. 3) Which of the following steps are taken in Delhi to reduce pollution?
(a) Use of leaded petrol
(b) Use of high sulphur petrol
(c) Use of catalytic converters in the vehicle
(d) Use of old vehicles
Que. 4) Explain. Why CNG is better for the fuel-containing vehicles?
Que. 5) What is the full form of CNG?
Answer Key
Que. 1)(d) Delhi
Que. 2) (b) CNG.
Que. 3) (c) Use of catalytic converters in the vehicle.
Que. 4) Answer: CNG is a compressed natural gas which burns most efficiently. This gas is cheaper than other fuel and thieves will not attack. Hence, CNG is better for the fuel containing vehicles.
Que. 5) Answer: The full form CNG is Compressed natural gas.
Case study 4
Presence of large amounts of nutrients in waters also causes excessive growth of planktonic (free-floating) algae, called an algal bloom. Which imparts a distinct colour to the water bodies. Algal blooms cause deterioration of the water quality and fish mortality. Some bloom-forming algae are extremely toxic to human beings and animals. You may have seen the beautiful mauve-colored flowers found on very appealingly-shaped floating plants in water bodies. These plants which were introduced into India for their lovely flowers have caused havoc by their excessive growth by causing blocks in our waterways. They grow faster than our ability to remove them.
These are plants of water hyacinth (Eichhornia crassipes), the world’s most problematic aquatic weed, alsocalled ‘Terror of Bengal’. They grow abundantly in eutrophic water bodies, and lead to an imbalance in the ecosystem dynamics of the water body.
Que. 1) An aquatic weed hyacinth is also called as ………………………………………………………………………………………..
(a) Terror of Bengal
(b) Terror of Nepal
(c) Terror of Gujrat
(d) Terror of Assam
Que. 2) Planktonic algae is also known as algal…………………………………………………………………………………….
(a) Hyacinth
(b) Mauva
(c) Bloom
(d) Weed
Que. 3) …………………..…………………………………………………. Type of algae is toxic to the animals.
(a) Root forming
(b) Bloom forming
(c) Flower forming
(d) Fungi forming
Que. 4) Write causes of mauve-coloured flowers.
Que. 5) What does algal bloom causes?
Answer Key
Que. 1)(a) Terror of Bengal
Que. 2) (c) Bloom.
Que. 3) (b) Bloom forming.
Que. 4) Answer: Mauva-coloured flower causes blocks in the waterways.
Que. 5) Answer: Algal bloom can cause fish mortality and water deterioration.
Case study 5
Solid wastes refer to everything that goes out in trash. Municipal solid wastes are wastes from homes, offices, stores, schools, hospitals, etc., that are collected and disposed by the municipality. The municipal solid wastes generally comprise paper, food wastes, plastics, glass, metals, rubber, leather, textile, etc. Burning reduces the volume of the wastes, although it is generally not burnt to completion and open dumps often serve as the breeding ground for rats and flies. Sanitary landfills were adopted as the substitute for open-burning dumps. In a sanitary landfill, wastes are dumped in a depression or trench after compaction, and covered with dirt everyday. A solution to all this can only be in human beings becoming more sensitive to these environment issues. All waste that we generate can be categorised into three types – (a) bio-degradable, (b) recyclable and (c) the non-biodegradable.
Irreparable computers and other electronic goods are known as electronic wastes (e-wastes). E-wastes are burried in landfills or incinerated. Over half of the e-wastes generated in the developed world are exported to developing countries, mainly to China, India and Pakistan, where metals like copper, iron, silicon, nickel and gold are recovered during recycling process.
Que. 1) In the solid waste, electronic good are ……………………………………………………………………………………..
(a) g-wastes
(b) s-wastes
(c) e-wastes
(d) p-wastes
Que. 2) The municipal type of solid waste is collected by ……………………………………………………………………………….
(a) Waster
(b) Municipality
(c) Thieves
(d) Servers
Que. 3) Which of the following is adopted as the substitute for open-burning dumps?
(a) Clean landfills
(b) Hygi landfills
(c) Wast landfills
(d) Sanitary landfills
Que. 4) What is meant by municipal solid waste?
Que. 5) Where does e-waste goes?
Answer Key
Que. 1)(c) e-wastes.
Que. 2) (b) Municipality.
Que. 3) (d) Sanitary landfills.
Que. 4) Answer: The waste which comes from stores, hospitals, homes and offices is known as municipal solid waste. Later it is disposed by municipality.
Que. 5) Answer: The e-waste mainly exported to the China, India and Pakistan for the recycling.
Case study 6
Integrated organic farming is a cyclical, zero-waste procedure, where waste products from one process are cycled in as nutrients for other processes. This allows the maximum utilisation of resource and increases the efficiency of production. Ramesh Chandra Dagar, a farmer in Sonipat, Haryana, is doing just this. He includes bee-keeping, dairy management, water harvesting, composting and agriculture in a chain of processes, which support each other and allow an extremely economical and sustainable venture. There is no need to use chemical fertilisers for crops, as cattle excreta (dung) are used as manure. Crop waste is used to create compost, which can be used as a natural fertiliser or can be used to generate natural gas for satisfying the energy needs of the farm. Enthusiastic about spreading information and help on the practice of integrated organic farming, Dagar has created the Haryana Kisan Welfare Club, with a current membership of 5000 farmers.
Que. 1) In the organic farming, cattle excreta were used as ………………………………………………………………………………….
(a) Waste
(b) Gas
(c) Fuel
(d) Manure
Que. 2) In the farming, integrated organic farming is a ……………………………………………………………………………. Waste procedure.
(a) Zero
(b) One
(c) Two
(d) Three
Que. 3) In the natural farming, ……………………………………………………………………………….. is used as a natural fertiliser and can generate natural gas.
(a) e-waste
(b) Crop waste
(c) Pond waste
(d) None of these
Que. 4) Who created Haryana Kisan Welfare Club?
Que. 5) Which processes are included in the integrated organic farming by Dagar?
Answer Key
Que. 1)(d) Manure.
Que. 2) (a) Zero.
Que. 3) (b) Crop waste.
Que. 4) Answer: The Haryana Kisan Welfare Club was created by Ramesh Chandra Dagar.
Que. 5) Answer: Processes like dairy management, composting, water harvesting and bee-keeping are included in the integrated organic farming by Dagar.
Case study 7
You have earlier studied in the Chemistry textbook of Class XI about ‘bad’ ozone, formed in the lower atmosphere (troposphere) that harms plants and animals. There is ‘good’ ozone also; this ozone is found in the upper part of the atmosphere called the stratosphere, and it acts as a shield absorbing ultraviolet radiation from the sun. UV rays are highly injurious to living organisms since DNA and proteins of living organisms preferentially absorb UV rays, and its high energy breaks the chemical bonds within these molecules. The thickness of the ozone in a column of air from the ground to the top of the atmosphere is measured in terms of Dobson units (DU). Ozone gas is continuously formed by the action of UV rays on molecular oxygen, and also degraded into molecular oxygen in the stratosphere. There should be a balance between production and degradation of ozone in the stratosphere. Of late, the balance has been disrupted due to enhancement of ozone degradation by chlorofluorocarbons (CFCs). CFCs find wide use as refrigerants. CFCs discharged in the lower part of atmosphere move upward and reach stratosphere. In stratosphere, UV rays act on them releasing Cl atoms.
Cl degrades ozone releasing molecular oxygen, with these atoms acting merely as catalysts; Cl atoms are not consumed in the reaction. Hence, whatever CFCs are added to the stratosphere, they have permanent and continuing effects on Ozonelevels. Although ozone depletion is occurring widely in the stratosphere, the depletion is particularly marked over the Antarctic region. This has resulted in formation of a large area of thinned ozone layer, commonly called as the ozone hole.UV radiation of wavelengths shorter than UV-B, are almost completely absorbed by Earth’s atmosphere, given that the ozone layer is intact. But, UV-B damages DNA and mutation may occur. It causes aging of skin, damage to skin cells and various types of skin cancers. In human eye, cornea absorbs UV-B radiation, and a high dose of UV-B causes inflammation of cornea, called snow-blindness, cataract, etc. Such exposure may permanently damage the cornea. Recognising the deleterious affects of ozone depletion, an international treaty, known as the Montreal Protocol, was signed at Montreal (Canada) in 1987 (effective in 1989) to control the emission of ozone depleting substances.
Que. 1) Which of the following acts as a shield that absorbs UV radiation?
(a) Waterways
(b) Stratosphere
(c) Atmosphere
(d) Clouds
Que. 2) UV rays are absorbed by ……………………………………………………………………………. In the living organisms.
(a) Liver
(b) DNA
(c) Proteins
(d) Both (b) and (c)
Que. 3) CFCs are …………………………………………………………………………………………..
(a) Calcifluorocarbons
(b) Chlorofluorocarbons
(c) Chloroflucalci
(d) Calcifluoricalci
Que. 4) Which type of UV radiation is absorbed by Earth’s atmosphere?
Que. 5) In which year Montreal protocol were signed?
Answer Key
Que. 1)(b) Stratosphere.
Que. 2) (d) Both (b) and (c).
Que. 3) (b) Chlorofluorocarbons.
Que. 4) Answer: UV-B radiation is absorbed by Earth’s atmosphere.
Que. 5) Answer: In 1987, The Montreal protocol were signed at Montreal.