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CBSE Class 12 Biology NCERT Exemplar Solutions: Chapter 16, Environmental Issues

Gurmeet Kaur

In this article we are providing the NCERT Solutions for CBSE Class 12 Biology chapter 16, Environmental Issues.  All the solutions are explained by the subject experts.

With the detailed and precise solutions provided here, solving the NCERT Exemplar problems becomes quite easy and manageable task for students. Not only do these NCERT Exemplar Solutions will strengthen a student’s foundation in the subject, but will also make them able to tackle different types of questions easily. This helps students prepare effectively for the boards as well as the medical entrance exams and score good marks.

Few problems along with their solutions from this chapter are given follows:

Q. Among the following which one causes more indoor chemical pollution?

(a) Burning coal

(b) Burning cooking gas

(c) Burning mosquito coil             

(d) Room spray

Ans. (a) Burning coal

Burning coal is the cause of major indoor chemical pollution. It releases carbon content in the atmosphere which combines with oxygen to form carbon dioxide, a threat to environment or may result in the formation of carbon monoxide which is a threat to human health.

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Burning of coal also releases inhalable particle nitrogen oxides sulphur dioxides metal and silicates. Although of mosquito coil and room spray causes indoor chemical pollution but their effects are long term.

Q. Use of lead-free petrol or diesel is recommended to reduce the pollutants emitted by automobiles. What role does lead play?

Ans. Tetraethyllead is added to petrol or diesel to reduce knocking in engine. Knocking severely damages the engine. But lead in this compound poses several environmental and health hazards. Motor vehicles equipped with catalytic converter need to use unleaded petrol because lead in the petrol, inactivates the catalyst and increases the hydrocarbon emission, there by harming the environment.

Q. List any two adverse effects of particulate matter on human health.

Ans. The fine particulate (PM of size 2.5 mm or less) can cause the following problems:

(i) Breathing and respiratory disorders

(ii) Irritation

(iii) Inflammations

(iv) Damage to the lungs and premature death

Q. Name an industry which can cause both air and thermal pollution and as well as eutrophication.

Ans. Chemical fertiliser unit, thermal power plant, refineries, smelting and metallurgical processing units, steel mills and the industries using steam or water as coolant cause both air and thermal pollution. The chemical release form these Industries (if rich in nitrogen and phosphorus) may result in eutrophication.

Find below the links to download Class 12 Biology NCERT Exemplar Solutions for chapter 16 - Environmental Issues:


Link to Download PDF

Multiple Choice Questions


Very Short answer type questions


Short answer type questions


Long answer types questions


CBSE Class 12 Biology Syllabus 2018 - 2019

Class 12 Biology NCERT Exemplar Problems:

The difficulty level of NCERT Exemplar problems is higher than the questions given at the end of each chapter of NCERT book. Practicing the NCERT Exemplar problems will help students to enhance their preparation level for boards and various other competitive examinations.

Questions from NCERT Exemplar are frequently asked in CBSE Class 12 boards and the medical entrance examinations.

Here, we are providing the NCERT Exemplar Problems for Class 12 Biology chapter - Environmental Issues, in the PDF form which students may download and solve them to analyse their preparedness for the exams.

 Main topics discussed in Class 12 Biology, Chapter 16- Environmental Issues, are:

Download the complete NCERT Exemplar book from the following link:

Class 12 Biology NCERT Exemplar Problems: Environmental Issues

Note: Once you are done with all the NCERT Exemplar problems, refer the solutions given above in this article to check the correctness of your own solutions and know the right way to get the perfect answers.

Class 12 Biology NCERT Solutions

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