Ozone is a protective blanket that is present in the stratosphere which protects earth from harmful effects of UV radiations that are present in sunlight.

Chlorofluorocarbons and other halogenated compounds cause ozone depletion.

Ozone is a protective blanket that is present in stratosphere which protects Earth from harmful effects of UV radiations that are present in sun light.

Ozone holes are formed in Antarctica and these are due to special clouds that form in the stratosphere called polar stratospheric clouds. Clouds usually do not form in stratosphere, this can happen only at such low temperatures. These clouds accumulate pollutants resulting in formation of ozone holes. 

• Stratosphere is the region of atmosphere where ozone layer is present, hence ozone depletion occurs in stratosphere.
  
• Biosphere is the region of surface and atmosphere of earth occupied by living organisms, hence unrelated to the question.
• Atmosphere is a broad term which becomes irrelevant when already a specific option ie stratosphere, is given in the choices.
• Microsphere is a small particle which has a different environment than its surroundings, hence incorrect.

The Government of India in its efforts to combat climate change launched its Nationwide programme on 30th June 2008. It was called the 'The National Action Plan on Climate Change'. It was adopted to address the future policies and programmes for climate change mitigation and adoption. The NAPCC comprises of  8 missions to accomplish the goals.

The greenhouse is the body which allows the shortwave incoming solar radiation to come but does not allow the longwave outgoing terrestrial infrared radiation to escape. Carbon dioxide, water vapour etc are the main gases of the greenhouse. The amount of greenhouse gases is increasing day by day which causes the increase of the temperature of the earth. In this way, global warming mainly caused by greenhouse gases.

Global warming refers to a gradual rise in atmospheric and ground surface air temperature. Emission of Carbon dioxide is one of the primary cause of global warming. As this gas allows the shortwave incoming solar radiation but does not allow the longwave outgoing terrestrial infrared radiation to escape. Thus an increase of carbon dioxide gas also increases in temperature of the earth which causes global warming.

Secondary,

Methane and Nitrous oxide.

Carbon dioxide,

D. Ozone

When the CFC refrigerants are leaked from refrigeration or air-conditioning systems, they drift around the lower layers of the atmosphere. Slowly they start infiltrating into the upper layers of the atmosphere and soon reach the ozone rich stratosphere, where they undergo major chemical changes.

When the industrial revolution started, the level of $CO _2$ in the atmosphere was around 280 parts per million by volume but that has risen to around 380 ppmv due to our burning of fossil fuels. Because of tremendous rise in $CO _2$ (about 35% rise) the global warming scenario has been deteriorated or faster. The melting of arctic ice, severe climate changes are some of the effects among many, of the global warming. Inefficiency in the use of fossil fuels which increased the $CO _2$ level by 17%.

Argon :-

The process of converting a non-forest land into a forest is known as Afforestation. Afforestation is highly important to maintain the biodiversity. Afforestation is necessary to combat the issues of global warming, soil erosion, pollution, and the maintenance of biodiversity and ecological balances. Afforestation is not a cause of environmental pollution.

Population, Industrialization and vehicles are the major causes of environmental pollution.

The ozone layer basically absorbs harmful emissions from the sun like the ultraviolet rays, which is why life on earth is able to thrive. No other planet known to man has conditions that can favor life, and without the ozone layer, Earth would also become unable to support life. Below are some things that would happen if the ozone layer was damaged to any extent.

Cancer: one of the things that would be frequently experienced by human beings on Earth is skin cancer. Since the layer would not be able to effectively block UV rays, human skin would most likely be endangered.

Cataracts: this refers to a condition where human vision goes blurred. Almost all human beings on earth would have some sort of visual impairment without the ozone layer.

Ozone layer depletion,

Ultraviolet rays,

Under Montreal Protocol,1987 the Kigali Amendment was agreed to phase down HFCs(HydroFluoroCarbons). It was on 15th October 2016 under United States leadership, 197 countries adopted this amendment under the Montreal Protocol in Kigali, Rwanda. It came into force on 1 January 2019. Under this amendment, the member States promised to reduce the production and consumption of HFCs by more than 80% over the next 30years.

Greenhouse gases are gases in Earth’s atmosphere that trap heat. They let sunlight pass through the atmosphere, but they prevent the heat that the sunlight brings from leaving the atmosphere. The main greenhouse gases are:

• Water vapor
• Carbon dioxide
• Methane
• Ozone
• Nitrous oxide
• Chlorofluorocarbons