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Important Questions for CBSE Class 12 Biology Chapter 16 - Environmental Issues 2023-24 (Not present in the current syllabus)

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Last updated date: 29th Mar 2024
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MVSAT 2024

CBSE Class 12 Biology Chapter-16 Important Questions - Free PDF Download

Free PDF download of Important Questions with Answers for CBSE Class 12 Biology Chapter 16 - Environmental Issues prepared by expert Biology teachers from latest edition of CBSE(NCERT) books. Register online for Biology tuition on Vedantu.com to score more marks in CBSE board examination.


Download CBSE Class 12 Biology Important Questions 2023-24 PDF

Also, check CBSE Class 12 Biology Important Questions for other chapters:

Competitive Exams after 12th Science

Study Important Questions for Class 12 Biology Chapter 16- Environmental issues

  5 Marks 

1. Pollutants released due to human activities (like effluents from industries and homes) can radically accelerate the ageing process of the water body. 

(a) Explain how this process occurs during the natural ageing of the lake.

Ans: Eutrophication is the term for this occurrence. Increased nutrients in the water, increased aquatic life, organic remnants deposited on the lake bottom, the lake becomes shallower and warmer, and eventually, turn into land owing to silt and organic debris deposition.

(b) Give the term used for accelerated ageing of water bodies. Also, give the term used for the natural ageing of lakes.

Ans: Cultural eutrophication or accelerated eutrophication. Natural ageing is Eutrophication.


2. In Arcata, the town’s people have created an integrated waste treatment process within a natural system. A citizen group called FOAM helps in the upkeep of this project. 

(a) What are the main steps in wastewater management done in this way?

Ans: Conventional sedimentation, filtering and chlorine treatment. Absorption and assimilation of pollutants are performed with the help of algae, fungi and bacteria.

(b) ‘Ecosan’ in Kerala and Sri Lanka is also an initiative for water conservation. How?

Ans: The term "Ecosan" has been derived from the term "ecological sanitation." Handling human excreta using dry composting toilets. Its practical, hygienic and cost-effective method


3. What are the contributions of Ahmed Khan in Bangalore and Ramesh Chandra Dagar 1 in Sonipat?

Ans: Integrated organic farming is a zero-waste, cyclical process in which waste products from one operation are recycled into nutrients for those other processes. This provides for the most efficient use of resources and boosts productivity levels. This is exactly what Ramesh Chandra Dagar, a farmer in Sonipat, Haryana, is doing. Natural gas is used to meet the farm's energy needs. Beekeeping, water harvesting, dairy management, composting, and agriculture are all part of a chain of activities that support each other and allow for a very cost-effective and long-term endeavour. Because cattle excreta (dung) has been used as manure, have no need to put artificial fertilisers on crops. Crop waste is turned into compost, that can be utilised as a natural fertiliser or used to produce natural gas to meet the farm's energy demands. Dagar founded the Haryana Kisan WelfareClub, which now has 5000 members and is dedicated to disseminating information and assisting farmers in the practice of integrated organic farming.


4. i) What is meant by ozone shield? 

Ans: TThe ozone layer in the atmosphere works as an ultraviolet absorber, shielding the earth from the detrimental effects of UV radiation. The ozone layer, also known as the ozone shield, is the highest layer of the atmosphere that is surrounded by ozone.

ii) Name two ozone-depleting substances? 

Ans: Chlorofluorocarbons (CFCs) and Halon are the two ozone-depleting substances.

iii) How do ozone-depleting substances affect ozone shields? 

Ans: When chlorine and bromine atoms come into contact with ozone molecules in the stratosphere, they are destroyed. A single chlorine atom might harm over 100,000 ozone molecules before being evacuated from the stratosphere. It's possible that ozone will be lost quicker than it can be replenished naturally.

iv) Write one damaging effect of ozone – depletion on humans & plants respectively?

Ans: It damages DNA and produces mutations in people, as well as causing skin ageing, damage to the skin, and skin cancer. It causes harm to plants, as well as premature death and restricted growth.


Important Related Links for CBSE Class 12 Biology

FAQs on Important Questions for CBSE Class 12 Biology Chapter 16 - Environmental Issues 2023-24 (Not present in the current syllabus)

1. How can I make the best study plan for Chapter 16 of Class 12 Biology? 

By following the given tips students can make a better study plan for Chapter 16 of Class 12 Biology:

  • For making a study plan, managing the time is the first step. Prepare a timetable so that you can study each chapter.

  • Refer to the NCERT Biology book for reading Chapter 16 and understanding concepts.

  • Attend all the class lectures plus the lab lectures to understand the topics.

  • Create notes of the chapter so that you can learn the important terminologies of the chapter. Revision notes and detailed explanation is easily available on Vedantu website and app.

2. What is the procedure to download the important questions of Chapter 16 of Class 12 Biology?

The procedure for downloading the important questions of Chapter 16 of Class 12 Biology is given below:

  • First of all, visit the page Important Questions of Class 12 Biology chapter 16.

  • After clicking the link, the official website of Vedantu will open on your device screen.

  • On Vedantu's official page you will find that important questions of Chapter 16 of Class 12 Biology are available.

  • The “Download PDF” option will be present at the top of the page.

  • Hit that option and your PDF file will get downloaded free of cost.

3. What are the topics covered in Chapter 16 of Class 12 Biology?

Chapter 16 of Class 12 Biology consists of the following topics:

  1. Air Pollution And Its Control:

  • Controlling Vehicular Air Pollution: A Case Study Of Delhi

  1. Water Pollution And Its Control:

  • Domestic Sewage and Industrial Effluents

  • A Case Study of Integrated Waste Water Treatment

  1. Solid Wastes:

  • Remedy for Plastic Waste (Case Study)

  1. Agro-Chemicals And Their Effects:

  • Case Study of Organic Farming

  1. Radioactive Wastes

  2. Greenhouse Effect And Global Warming

  3. Ozone Depletion in the Stratosphere

  4. Degradation By Improper Resource Utilisation and Maintenance

  5. Deforestation:

  • People's Participation in Conservation of Forests (Case Study)

4. Describe the working of the electrostatic precipitator.

The electronic precipitator removes 99% of particulate matter which is present in the exhaust using a thermal power plant:

  • The electrode wires provide a corona releasing electrons and are maintained at several thousand voltages.

  • These electrons get attracted towards the dust particles. They also offer a negative charge to these particles. 

  • The plates that collect the particles are grounded and get attracted towards the dust particles.

  • The plates should have air with low velocity so that dust particles can fall.

5. What are the characteristics and uses of the modern landfill site?

(a) Characteristics:

  • To prevent waste from being blown by wind, integument and compaction is done.

  • To contain leachates such as plastic liners or lining clay, procedures are done.

  • Landfill gas extraction systems are installed for extracting gas which is used in the generation of power.

(b) Uses:

  • They help in the prevention of waste through recovery and recycling of waste.

  • To prevent the essential transport of waste, a uniform cost for the disposal of waste is created.

  • They help in decreasing the risk to the environment and human health that emerged from the wastes.