To reduce global warming following measures must be taken:
(i)  cutting down the use of fossil fuel
(ii)  Improving efficiency of energy usage
(iii) Reducing deforestation
(iv) Planting trees and slowing down the growth of human population.

Greenhouse gas like co$ _2$, methane, CFC absorbs the radiation reflected from the earth's surface in the form of heat and increases the atmosphere's temperature is called as greenhouse effect which leads to the global warming.

Global warming causes melting of polar ice caps. This decreases the size of glaciers and leads to the rise of oceans.

Global warming is the biggest challenge for the developing countries like India. The rapid increase in human population and the increased levels of pollution are the major contributors of global warming.The percentage of heat-trapping carbon dioxide (CO$ _2$) increases due to the burning of  fossil fuels to generate electricity, fuel our cars, and heat our homes. Deforestation also increases the concentration of carbon dioxide in the atmosphere.

Modern human activities are responsible for the release of huge quantities of CO$ _2$ in the atmosphere. The major activities, which contribute towards this, are burning of fossil fuels and cultivation of the soil. Although CO$ _2$ is not considered as a pollutant, an increase in its proportion in the atmosphere can lead to global warming through increased greenhouse effect. 

The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl nuclear power plant in Ukraine. In this accident, large quantities of radioactive particles were released into the atmosphere, which spread over much of the western USSR and Europe. It was the worst nuclear accident in history.

The greenhouse effect is caused by the greenhouse gases. The gases methane, carbon dioxide, and water vapour trap the solar radiations which need to be reflected back to the atmosphere and increase the temperature of the earth. The greenhouse is considered as the direct cause of global warming.

CFCs are used as coolants in refrigerators, coolers, etc. The CFCs causes the breaking of the ozone molecule which forms the oxygen radical and O$ _2$. So, the presence of CFCs in the atmosphere results in the depletion of the ozone layer and allowing the penetration of the harmful UV radiations from the sun into the Earth's atmosphere. 

Carbon dioxide is a greenhouse gas. It is released constantly by burning of fuels in industries, automobiles etc. It causes a severe increase in atmospheric temperature and leads to global warming. It contributes nearly 60% of global warming.

When carbon dioxide and other air pollutants are collected in the atmosphere they absorb sunlight that has bounced from the earth’s surface. This leads to an increase in the earth's average surface temperature and is called global warming. Carbon dioxide emissions from burning fossil fuels and deforestation are the primary cause of global warming. Thus the correct answer is option C.

Global warming is caused by increased atmospheric concentration of $CO _2$ and other green house gases. As greenhouse gases absorbs the solar energy when radiation is reflected back to the atmosphere from earth's surface and increase the earth's temperature. Eutrophication refers to the presence of excess organic compounds in water. Depletion of the ozone layer is caused by the excess release of chlorine and bromine-containing the chemical in the atmosphere. Acid rain is the result of increased sulphur and nitrogen oxide levels in the atmosphere. Slow metabolism and excretion of pesticides causes their accumulation in fat tissues of organisms and is referred to as biomagnifications. The correct answer is A.

When carbon dioxide and other air pollutants are collected in the atmosphere they absorb sunlight that has bounced from the earth’s surface. This leads to an increase in the earth's average surface temperature and is called global warming. When there is no carbon dioxide in the atmosphere, the temperature of the Earth's surface will be less than the present temperature. 

When carbon dioxide and other air pollutants are collected in the atmosphere they absorb sunlight that has bounced from the earth’s surface. This leads to an increase in the earth's average surface temperature and is called global warming. When there is no effect of the global warming, the temperature of the Earth's surface will decrease. 

The unplanned clearing of land leads to loss of habitats and also it leads to loss of biodiversity.

Strategies to deal with global warming include (i) Complete replacement of chlorofluorocarbons with substitutes that have little effect on ozone and global warming, (ii) Increasing vegetation cover or forests for photosynthetic utilisation of carbon dioxide, (iii) Reduction in the use of nitrogen fertilizers and instead relying more on nitrogen fixation, (iv) Limiting use of fossil fuels by developing alternate sources of energy eg Solar energy, wind energy etc.

The warming up of global atmosphere present day is due to the increase in green house effect. Green house effect (GHE) describe the roles of water vapour, $CO _2$ and other trace gases in keeping the Earth's surface warmer than it would be otherwise.These radiatively active gases are relatively transparent to incoming shortwave radiation (visible spectrum), but are relatively opaque to outgoing reradiating (infrared rays) longwave radiation. The latter radiation, which would otherwise escape to space, is trapped by these gases within the lower levels of the atmosphere. The subsequent reradiation of some of the energy back to the surface maintains surface temperature higher than they would be if the gases were absent (without the green house effect the Earth's average global temperature would be 18 degree celsius rather than the present 15 degree celsius). There is concern that increasing concentration of the green house gases including CO2, CH4, and man made chlorofluorocarbons (CFCS), may enhance the green house effect and cause global warming. Ozone layer present in the stratosphere is depleted by the aerosols and chloroflurocarbons. Ozone protects the earth from high energy ultra violet radiation. So, the correct answer is 'If both the assertion and reason are true but the reason is not a correct explanation of the assertion'

Global warming occurs when carbon dioxide and other air pollutants called the greenhouse gases collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface.

Global warming refers to the increase in the average temperature of earth due to an excessive amount of greenhouse gases namely CO$ _2$, CH$ _4$ etc. It can be controlled by reducing deforestation. A high plant cover utilizes the major amount of CO$ _2$ from the air. Also another method of control is cutting down the use of fossil fuels which otherwise emits greenhouse gases like CO$ _2$, N$ _2$O etc.

The poisonous gases released in the environment traps the radiations on the earth and increases temperature which leads to global warming. Methane is a more potent greenhouse gas than $CO _2$, there is over 200 times more $CO _2$ in the atmosphere. For example $CO _2$ levels are 380 ppm (parts per million), while methane levels are 1.75 ppm. Hence, the amount of warming methane contributes is calculated at 20% of the warming $CO _2$ contributes.

• As individuals, we can help by taking action to reduce our personal carbon emissions.
•  But to fully address the threat of global warming, we must demand action and support and implement a comprehensive set of climate solutions:
•  Expand the use of renewable energy and transform our energy system to one that is cleaner and less dependent on coal and other fossil fuels.
•  Increase vehicle fuel efficiency and support other solutions Place limits on the amount of carbon that polluters are allowed to emit. 
• Build a clean energy economy by investing in efficient energy technologies, industries, and approaches. 
• Reduce tropical deforestation and its associated global warming emissions.
• Hence, Increasing the use of air conditioners, refrigeration unit and production of plastic foams and propellants in aerosol spray cans is not a correct approach to reduce global warming. 
• So, the correct answer is 'Increasing the use of air conditioners, refrigeration unit and production of plastic foams and propellants in aerosol spray cans'.

Global warming is caused by increased concentration of greenhouse gases (carbon dioxide is one of the greenhouse gas) in the atmosphere. Increased organic matter in lakes causes eutrophication. Ozone depletion is mainly related to the use of CFC-based products. Acid rain is the result of increased sulphur and nitrogen oxide levels in the atmosphere. Increased use of pesticides causing the death of predators will cause accumulation of nonbiodegradable compounds in the food chain. Thus, the correct answer is option A. 

The Ultra-violet radiations are the potent mutagens as they are capable of distorting the structure of the DNA. The UV radiations cause the adjacent pyrimidines residues (thymine and cytosine) to form hydrogen bonds with each other rather than the corresponding purine residues. Generally, the thymine dimers are seen as immediate effects of the UV radiations. Due to this type of mutation, the errors in replication of DNA are frequent to observe. The breaking of hydrogen bonds between the two complementary DNA strands occurs due to increase in temperature. This is not considered as a mutation because when normal conditions arrive the hydrogen bonds can be formed again.

Global warming refers to the overall increase in the tropospheric temperature reflected on the earth's surface. Developing substitutes for chloroform will not allow the build of chloroforms in the atmosphere. Minimal use of nitrogen fertilizers will not allow nitrogen oxides to cause secondary pollutants. Increase in vegetation like forests will make sure that carbon dioxide is used and so it will not cause the greenhouse effect. Limited use of fossil fuels will not add carbon dioxide, methane, oxides of sulphur etc and thus environment can be saved from their deleterious effects. On the other hand increase use of ACs, refrigerators, production of plastic forms and aerosol spray can propellants are harmful to the environment in a great deal because they cause ozone hole as well as global warming.

The Kyoto protocol is an international treaty which extends the 1992 united nations framework convention on climate change (UNFCC) that commits state parties to reduce greenhouse gas emissions, based on the scientific consensus that global warming is occurring.

Carbon dioxide is main cause of green house effect. The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapor, carbondioxide, nitrous oxide, ozone, methane, for example) trap energy that comes from the sun.
Thus, increase of carbon dioxide gas in atmosphere will cause increase in temperature.

The average temperature of the earth remains fairly steady as compared to that of the moon because of the earth's atmosphere. Atmosphere of earth absorbing ultraviolet solar radiation, warming the surface through heat retention (green house effect), and reducing temperature extremes between day and night. Moon has no atmosphere. 

The effects of an increase in global temperature include a rise in sea level rise (due to melting of snow and ice and because water above 3.98 C expands as it warms), widespread melting of snow and ice, increased heat content of the oceans, increased humidity, and the earlier timing of spring events.
Option D is correct.

    The short wavelength (high frequency) infrared radiations  come from sun to earth's surface and after reflection from surface , turn into long wavelength infrared radiations , these long wavelength radiations are absorbed by green house gases .

The correct answer is option(A).

Due to global warming the temperature of earth's atmosphere in increasing, and the temperature at poles is also increasing. This increase in temperature at poles will melt the ice on poles , and will melt the glaciers and after some time the poles will be iceless. This will result in increase in the level of oceans which in turn may sink the coastal land areas.

Global warming is caused primarily due to emission of carbon dioxide. Other pollutants contributing to global warming includes methane, nitrous oxide and CFCs.

Global warming has certain changes in weather that inturns changes rainfall patterns that increases disease,so only option incorrect is decreament in deseases.

The World Nature Organization (WNO) is dedicated to the protection of the environment at international level. Its main focus is on energy efficiency, climate protection, sustainable development and a sustainable energy supply. As a permanent platform, the WNO tries to build bridges between business interests as well as development and environmental protection while, at the same time, making the economic value of nature apparent.

Global warming could affect agriculture and farming in several ways.

All the deeds which will reduce the emissions of greenhouse gases will stop climate change.All the given options, directly or indirectly affects the concentration level of greenhouse gases.

• The Arctic, Antarctic, Siberia, and other frozen regions of the earth might experience more plant growth and milder climates.
• The next ice age could possibly be prevented.
• The Northwest passage through the formerly icy Canadian Arctic Archipelago could arguably open up to transportation.
• Fewer deaths or injuries would occur due to arctic conditions.
• Longer growing seasons could mean increased agricultural production in some areas.
• Previously untapped oil and gas reserves might become available.

The world average temperature is rising due to the greenhouse effect caused by increasing levels of greenhouse gases, especially carbon dioxide. When the global temperature changes, the changes in climate are not expected to be uniform across the Earth. In particular, land areas change more quickly than oceans, and northern high latitudes change more quickly than the tropics, and the margins of boime regions change faster than do their cores.

The ozonosphere contains a layer of ozone gas which absorbs ultraviolet radiations and thus prevent us from harmful effects like skin disease.

• The Arctic, Antarctic, Siberia, and other frozen regions of the earth might experience more plant growth and milder climates.
• The next ice age could possibly be prevented.
• The Northwest passage through the formerly icy Canadian Arctic Archipelago could arguably open up to transportation.
• Fewer deaths or injuries would occur due to arctic conditions.
• Longer growing seasons could mean increased agricultural production in some areas.
• Previously untapped oil and gas reserves might become available.

Global heating will effect on type of crops and its various natural features.Moreover humans will feel the extra heat and also the deplete of ozone gas.

The effects of global warming or climate damage include far-reaching and long-lasting changes to the natural environment, to ecosystems and human societies caused directly or indirectly by human emissions of greenhouse gases. It also includes the economic and social changes which stem from living in a warmer world. Global warming stresses ecosystems through water shortages in already water-scare areas. increased deaths from heat waves, extension of additional species of animals and plants etc.

When we are nearer to the ice, our body temperature is higher than the surrounding temperature. So heat flows from out body to the surrounding resulting in lowering the body temperature. Thus we feel cold when being nearer to the ice.

Two major mechanisms are causing sea level to rise.
First, shrinking land ice, such as mountain glaciers and polar ice sheets, is releasing water into the oceans.
Second, as ocean temperatures rise, the warmer water expands. 
The warming of the atmosphere caused by increases in greenhouse gases is melting glaciers and causing ocean water to warm and expand thermally. Both effects increase the volume of the ocean, raising its surface level.
Thus Option D is correct.

During winter, our body temperature is higher than the surrounding temperature. So heat flows from out body to the surrounding resulting in lowering the body temperature. Thus we feel cold during winter.

Cold air tries to carry body heat away. Blankets form a barrier between the body and cold air. Hence heat doesn't transfer through the blankets as air will not flow through the blankets.

If an ideal thermally conductive black body were the same distance from the Sun as the Earth is, it would have a temperature of about 5.3 C. However, since the Earth reflects about 30% of the incoming sunlight, this idealized planet's effective temperature (the temperature of a black body that would emit the same amount of radiation) would be about 18 C. The surface temperature of this hypothetical planet is 33 C below Earth's actual surface temperature of approximately 14 C. The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect.
Thus Option A is correct.

    Due to global warming the temperature of earth's atmosphere in increasing , and the temperature at poles and high mountains is also increasing . This increase in temperature will melt the ice on poles and peaks of mountain and will melt the glaciers . This will result in rise in the level of sea .

Due to global heating temperature of the atmosphere increases,which inturns requires its controlling measures that consequently involves new technologies and hence becomes a burden in terms of money.

A hurricane is a large rotating storm with high speed winds that forms over warm waters in tropical areas. According to 2006 studies by the National Oceanic and Atmospheric Administration, the strongest hurricanes in the present climate may be upstaged by even more intense hurricanes over the next century as the Earth's climate is warmed by increasing levels of greenhouse gases in the atmosphere. Hurricanes will get worse and hurricanes like katrina will be common on the coastal area. It is predicted that the global temperature would increase by $2.5^0F$ to $10^0F$. 

A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect on planets. The primary greenhouse gases in Earth's atmosphere are water vapour $(H _2O)$, carbon dioxide $(CO _2)$, methane $CH _4)$, nitrous oxide $(N _2O)$ and ozone $(O _3)$. 

Climate change could result in global, large-scale changes in natural and social systems.Examples include the possibility for the Atlantic Meridional Overturning Circulation to slow- or shutdown, which in the instance of a shutdown would change weather in Europe and North America considerably, ocean acidification caused by increased atmospheric concentrations of carbon dioxide, and the long-term melting of ice sheets, which contributes to sea level rise.

Global warming has brought about possibly irreversible alterations to Earth's geological, biological and ecological systems. Global warming affect on climate can adversely affect humans. An increase in temperature can result in a longer life cycle for diseases. Global warming can affect our future ability to obtain food.