Tag: the earth and its living world

Water use is increasing every year since 1950 by 4% to 8%.  Electricity water use increased almost 400% since 1950. The use of irrigation water increased by about 29% since 1950. Maximum water is used to grow food for increasing population. Apart from this, the majority of water is used for thermoelectric power and as public supply.

Ozone layer is part of earth's atmosphere. Ozone is basically found in stratosphere. Ozone layer contains high concentration of ozone formed due to reaction of oxygen with UV radiations. It is vital to human life on earth because it absorbs biologically harmful ultraviolet radiations from sun. Direct exposure of such rays can cause serious illness and skin problems. However ozone chemically forming in earth's surface is lethal in many ways.

• Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona at the base of the Santa Catalina Mountains.
• Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the universe.
  
• It is a glass dome covering an area of 3.5 acres with 4000 representatives of most ecosystems and eight human beings in order to prepare a prototype of the space colony. 
• So, the correct answer is 'Biosphere 2'.

The ozone layer in the stratosphere absorbs solar UV-B (280-320 nm) which is the most harmful part of the ultraviolet. Thus it acts as protector gas for plants, animals by absorbing harmful UV radiation in the stratosphere and as pollutant around the ground level. Nature intended that the stratospheric ozone layer would block the sun's harmful ultraviolet rays.. (CFC), which contains chlorine, an ozone destroyer.

The concentration of ozone varies with an altitude of the atmospheric layers. Ozone is basically stratospheric gas. The reaction of the oxygen with the UV radiations result in the formation of the ozone layer. Peak concentration, an average of 8 molecules per million molecules occur above the altitude of 30kms from the earth's surface which is roughly 20 miles. This is the height that corresponds to the stratosphere.

The high altitude supersonic aircraft flying in stratosphere zone emit nitrous oxides which can destroy ozone significant quantity being highly reactive. Aerosols are tiny particles in the air resulting from the burning of fossil fuels, emission from cars and factories are also causal factors of aerosols. It may be referred to the spray cans that release chlorofluorocarbons which cause the breakdown of ozone Into oxygen once these compound reach the stratosphere.

The water present on earth in form of lakes, oceans, rivers, etc is called hydrosphere. About 2/3rd (71%) of earth's crust is covered by water. This layer contains water which regulates the atmospheric temperature and ecosystem and also maintains the aquatic life on earth. About 2.5% of hydrosphere constitutes of fresh water. So, the correct option is C.

a) The biosphere is the sum of all ecosystem. It is the layer of earth where life exists.