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Published on: 09/09/2019
Botany - Environmental Issues
Download Tamil Nadu 12th Standard Biology question papers, model tests, one-mark questions, important questions, and public exam papers in PDF format. Free study materials and answer keys for TN State Board students.
Questions + Answers key
Take MCQ Biology Test1.
The plants which are grown in silvopasture system are ______.
Sesbania and Acacia
Solenum and Crotalaria
Clitoria and Begonia
Teak and sandal
2.
3.
The unit for measuring ozone thickness _____.
Joule
Kilos
Dobson
Watt
4.
Deforestation means ______.
growing plants and trees in an area where there is no forest
growing plants and trees in an area where the forest is removed
growing plants and trees in a pond
Removal of plants and trees
5.
Which of the following would most likely help to slow down the greenhouse effect.
Converting tropical forests into grazing land for cattle.
Ensuring that all excess paper packaging is buried to ashes.
Redesigning landfill dumps to allow methane to be collected.
Promoting the use of private rather than public transport.
6.
How do forests help in maintaining the climate?
7.
Expand CCS. (or) What is CCS?
8.
9.
10.
Which one gas is most abundant out of the four commonest greenhouse gases? Discuss the effect of this gas on the growth of plants?
11.
How do sacred groves help in the conservation of biodiversity?
12.
What are the effects of deforestation and benefits of agroforestry?
13.
1.
(a)
Sesbania and Acacia
2.
(c)
3.
(c)
Dobson
4.
(d)
Removal of plants and trees
5.
(c)
Redesigning landfill dumps to allow methane to be collected.
6.
(a) Trees provide micro climate for crops and maintain O2 - CO2 balance atmospheric temperature & relative humidity
(b) Suitable for dry land where rainfall is minimum hence it is a good system for alternate land use pattern
7.
CSS - Carbon Capture and Storage.
8.
9.
10.
Most abundant gas - CO2
Effect of CO2 on the growth of plants
(i) Change in flowering seasons and pollinators
(ii) Change in Species distributional ranges
(iii) Species extinction
(iv) Low agricultural productivity in tropics
(v) Frequent heat waves (Weeds, pests, fungi need warmer temperature)
(vi) Increase of vectors and epidemics
(vii) Strong storms and intense flood damage
(viii) Water crisis and decreased irrigation
11.
(i) They help for detailed floristic and faunistic studies
(ii) These groves provide a number of ecosystem services to the neighborhood like protecting watershed, fodder, medicinal plants and microclimate control
12.
Effects of deforestation:
(i) Burning of forest wood release stored carbon, a negative impact just opposite of carbon sequestration,
(ii) Trees and plants bind the soil particles. The removal of forest cover increases soil erosion and decreases soil fertility. Deforestation in dry areas leads to the formation of deserts.
(iii) The amount of runoff water increases soil erosion and also creates flash flooding, thus reducing moisture and humidity.
(iv) The alteration of local precipitation patterns leading to drought conditions in many regions. It triggers adverse climatic conditions and alters water cycle in the ecosystem.
(v) It decreases the bio-diversity significantly as their habitats are disturbed and disruption of natural cycles.
(vi) Loss of livelihood for forest dwellers and rural people.
(vii) Increased global warming and account for one-third of total CO2 emission.
(viii) Loss of life support resources, fuel, medicinal herbs, and wild edible fruits.
Benefits of agroforestry:
(i) It is an answer to the problem of soil and water conservation and also to stabilize the soil (salinity and water table) reduce landslide and water run-off problem.
(ii) Nutrient cycling between species improves and organic matter is maintained.
(iii) Trees provide a micro climate for crops and maintain O2 - CO2 balanced, atmospheric temperature and relative humidity.
(iv) Suitable for dry land where rainfall is minimum and hence it is a good system for alternate land use pattern.
(v) Multipurpose tree varieties like Acacia are used for wood pulp, tanning, paper, and firewood industries.
(vi) Agroforestry is recommended for the following purposes. It can be used as Farm Forestry for the extension of forests, mixed forestry, shelterbelts, and linear strip plantation.
13.
12th Standard Syllabus & Materials
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Tamilnadu Stateboard 12th Standard Subjects

Maths

Chemistry

Physics

Biology

Computer Science

Business Maths and Statistics

Economics

Commerce

Accountancy

History

Computer Applications

Biology

Computer Technology

Computer Applications

Computer Science

Business Maths and Statistics

Commerce

Economics

Maths

Chemistry

Physics

Computer Technology

History

Accountancy

Tamil

English

French
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