Tuesday, April 10, 2018

AHSEC Class 11: Environmental Education Solved Question Papers' 2016

Full Marks – 30
Time – 3 hour
1. Write very short answer of the following questions:                                 1x10=10
a)      Name any two manmade environmental problems.
Ans: Air Pollution, Noise Pollution
b)      Define the term ‘species’.
Ans. Groups of organisms that resemble one another in appearance, behaviour, chemistry and genetic structure from a species.
c)       Name any two non metallic minerals.
Ans: Non metallic minerals: e.g., graphite, diamond, quartz, feldspar etc.
d)      Name the atmospheric region fastest from the earth surface.
Ans: Exosphere
e)      Give example of natural source of noise pollution.
Ans: Atmospheric noise- due to spurious radio frequency waves due to lightning and other natural disturbances occurring in the atmosphere. Natural phenomena like lightning, thunder, volcanic eruption, earthquake, sound of the ocean waves, etc.
f)       State two ways for which decomposers are useful.

Ans: a) Decomposers and scavengers break down dead plants and animals. They also break down the waste (poop) of other organisms. b) Decomposers are very important for any ecosystem. If they weren't in the ecosystem, the plants would not get essential nutrients, and dead matter and waste would pile up. 
g)      Name two toxic gases emitted by industries.
Ans: ammonia (NH3), carbon dioxide (CO2), carbon monoxide (CO), hydrogen chloride (HCl), nitrous oxide (N2O)
h)      Name the biosphere reserve of Assam which is the home of golden langur.
Ans: Manas National Park
i)        Which State of North-East India is famous for uranium?
Ans: Meghalaya
j)        Every year on which date is the International Day for the Preservation of the Ozone Layer observed?
Ans: 16th September
2. Write short answers of the following questions (any five):                    2x5=10
a)      What is an ecological pyramid? Name different types of ecological pyramid.
Ans: The graphical representation of the trophic structure and functions of an ecosystem with producers at the base and successive trophic levels of consumers forming the higher layers (apex) is known as ecological pyramids.
b)      What is consumptive use of biodiversity?
Ans: Biodiversity provides a range of goods, from agricultural crops to medicines and fibres, to which a direct value and cost can be assigned. This direct economic value of the natural environment can be divided into those associated with consumption and production i.e. consumptive use and productive use values.
c)       Write a short note on forest resources of Assam.
Ans: Forests in Assam are rich in valuable trees such as, Sal, Simalu, Saral, Segun, Agar, Bossum, Bamboo, Cane, Medicinal herbs, etc. They also supply fruits, fuel andfodder. These forest resources have helped the growth of forest-based industries such as, plywood and paper industries.
d)      Distinguish between a situ conservation and ex situ conservation of biodiversity.
Ans. In-situ conservation is conservation of wild species of flora and fauna in their natural habitat i.e. on site preservation e.g. biosphere reserves, national parks, wildlife sanctuaries, reserve forests etc. Ex-situ conservation is the conservation of plants and animals away from their natural habitat.
e)      Explain the formation of acid rain.
Ans: Oxides of sulphur and nitrogen originating from industrial operations and fossil fuel burning are the major sources of acid forming gases in the atmosphere. When sulphur dioxide and nitrogen oxides are transported by prevailing winds, they come in contact with water vapour and form sulphuric acid and nitric acid respectively. These chemical substances come down to the earth’s surface in two forms – wet and dry (as acidic particles). The resulting mixture is called acidic deposition or commonly called acid rain.
f)       Describe the causes of soil degradation.
Ans: Causes of soil degradation:
1)      Soil erosion: Loss of top soil.
2)      Water Logging: Accumulation of excess water under the ground.
3)      Salinization: It is the accumulation of soluble salts of sodium, magnesium and calcium in soil to the extent that soil fertility is severely affected.
4)      Contamination of soil with industrial waste like heavy metals, pesticides, fertilizers etc.

g)      What are greenhouse gases and how do they affect the climate?
Ans: During the day, energy from the sun (largely in the visible part of the spectrum) is absorbed by the earth’s surface. If all this energy were to be absorbed completely, the earth would gradually become hotter. But in reality, the earth both absorbs and simultaneously releases it in the form of infra red radiations (long wavelength, less energetic). All the rising heat is not lost to space, but is partly absorbed by some gases present in the atmosphere in very small quantities, called the Greenhouse Gases (GHGs). The major GHGs are carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs), water vapour and ozone. These gases re-emit some of the heat to the earth surface. This effect is called greenhouse effect.
h)      What measures will you adopt for energy conservation?
Ans: The following measures for energy conservation can be adopted in initial steps:
(1)    More technological innovation contributing efficient energy saving.
(2)    Unnecessary use of electricity should be prohibited.
(3)    Switch off the street lights early in the morning.

3. Answer any two of the following questions:                                  5x2=10
a)      Describe different segments of environment.
Ans: There are four segments of the environment.
(1)    Atmosphere.
(2)    Hydrosphere.
(3)    Lithosphere.
(4)    Biosphere.
All the air in the atmosphere makes up the atmosphere. The atmosphere is a mixture of nitrogen (about 78%), oxygen (about 21%), and other gasses (about 1%) such as carbon dioxide (0.039%), argon (0.93%) and the rest are trace gases (krypton, neon, helium , and xenon).
The hydrosphere includes all the gaseous, liquid, and solid water of the planet earth. The hydrosphere stretches all the way from the Earth’s surface downward numerous miles into the lithosphere and high above the crust into the atmosphere.
The lithosphere is made up of all the hard and solid land mass on the earth’s surface, the semi-solid rocks (molten materials) underneath the earth crust, and the liquid rocks in the inner core of the earth. 
The hydrosphere includes all the gaseous, liquid, and solid water of the planet earth. The hydrosphere stretches all the way from the Earth’s surface downward numerous miles into the lithosphere and high above the crust into the atmosphere.
b) Discuss the major threats to biodiversity.
Ans: The term ‘biological diversity’ commonly shortened to biodiversity refers to the number, variety, and variability of all life forms on earth. There have been threats of biodiversity from different angles such as:
a)      Habitat destruction.
b)      Overgrazing.
c)       Poaching.
d)      Natural calamities.
e)      Climate change and global warming.
f)       Bio piracy.
c) Describe the man-made sources of air pollution.
Ans: Air pollution comes from many different sources.  Some sources are natural such as windblown dust and smoke from wildfires.  Other sources are man-made such as emissions from factories, power plants, automobiles, construction equipment, small businesses (I.E. print shops, auto body shops, gas stations, dry cleaners, etc.) and open burning.  These air pollutants can be solids, liquids, or gases.  Air pollution can cause adverse health effects in humans and animals, influence climate change, and damage our environment. Although we may not have control over natural sources of air pollution, we do have control over man-made sources.  Various agencies create air quality regulations requiring the reduction of pollutants but regulations can only do so much.  It is also up to individuals to understand how the decisions that they make everyday can contribute to air pollution. 
Some the important man-made source of air pollution are:
1)      Deforestation.
2)      Burning of fossil fuels.
3)      Emission from vehicles.
4)      Rapid industrialization.
5)      Modern agricultural practices.
d) Write an account on concept of sustainable development.
Ans: It is the development, which will allow all future generations to have a potential average quality of life, which is at least as high, which is being enjoyed by the current generation. The following strategies should be adhered to, for sustainable development:
1. Use of Non-conventional source of Energy like wind and solar says are cleaner and greener technologies, which can be effectively used to replace thermal and hydropower.
2. Use of CNG as fuel in public transport system has lowered air pollution and the air has become cleaner. The use of LPG and Gobar Gas is being promoted which reduces air pollution.
3. Establishment of Mini-Hydel plants in mountain regions to generate electricity through mini Hydel plants.