Bihar Board - Class 12 Biology - Chapter 16: Environmental Issues Short Answer Question

1. 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 aging, damage to the skin, and skin cancer. It causes harm to plants, as well as premature death and restricted growth.

2.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.

3. 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.

4. Pollutants released due to human activities (like effluents from industries and homes) can radically accelerate the aging process of the water body.  Explain how this process occurs during the natural aging 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.

5. Define cultural eutrophication.

Ans. It is a phenomenon wherein effluents from homes and industries fuel the cultural and natural aging process of water bodies which otherwise takes thousands of years.

6. Why does the road life factor increase by a factor of three upon addition of blends of bitumen and poly blend?

Ans. Plastic increases the melting point of bitumen that prevents its melting given India’s hot climatic conditions, where temperature frequently crosses 50℃. Because of the plastic blend, rainwater will not be able to penetrate.

7. Define algal bloom.

Ans. Presence of organic matter in water acts as a food source resulting in extensive growth of planktonic algae in water bodies and is called an algal bloom.

8. What is biomagnification?

Ans. Increase in the concentration of toxic substances at consecutive trophic levels in the food chain is referred to as biomagnification.

9. How can electronic wastes be treated in the most efficient way?

ans. Recycling. It has two advantages:

• It blocks the entrance of toxic substances into the fragile environment and groundwater through a landfill.

• It lowers the utility and mining of primary raw materials.

10.What is the Environment? ans.An Environment is everything that is around us, which includes both living and nonliving things such as soil, water, animals and plants, which adapt themselves to their surroundings. It is nature’s gift that helps in nourishing life on the earth.

11..What is Biodiversity Conservation?

Ans. Biodiversity conservation means protection, conservation and management of biodiversity in order to obtain sustainable benefits for future generations.

12. .What is Deforestation?

Ans. Deforestation can be defined as the large-scale removal of trees from forests (or other lands) for the facilitation of human activities. It is a serious environmental concern since it can result in the loss of biodiversity, damage to natural habitats, disturbances in the water cycle, and soil erosion. Deforestation is also a contributor to climate change and global warming.