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One fifteenth.

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Q: What is one-third of one-fifth?
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What is onefifth of 120?

24


What is percent is equal to onefifth?

1/5 = 20%


What is the answer to in a decimal onefifth?

1/5 = 0.20 in decimal


How many ounces in a teal?

one and onethird ounces.


How much of Norway is north of the arctic circle half onethird onesix?

half?


How do you find onefifth of a number?

divide the number by the denominator of the fraction 100 / 5 = 20 1/5 of 100 = 20 20 * 5 = 100


How many ounces in onethird cup of salt?

2.64 oz 1 cup = 8 ounces 1 ounce = 0.12 cup


What is a equivalent fraction for 412?

412/1 is an equivalent fraction.


What is onethird as a decimal?

0.333... Also called 0.3 recurring (usually represented with a dot above the 3) as there are an infinite number of 3s after the decimal point.


What is the number that is 5 more than the number which is one fifth of onefifth of one half of 1050?

(1/2)(1/5)(1/5)(1050)+5=(1/50)(1050)+5=(1050/50)+5=21+5=26


How would i set up this equation Two consecutive numbers onefourth of the first number is one more than onefifth of the second number?

Suppose the first number is x. Then the second number is x+1. A fourth of the first number is x/4 A fifth of the second number is (x+1)/5 So the equation is x/4 = (x+1)/5 + 1 Multiplying though by 20: 5x = 4x + 4 + 20 = 4x + 24 Subtracting 4x from both sides: x = 24


You want to know about population characteristics and change in India?

PopulationIntroduction: The people are important to develop the economy and society. The people make and use resources and are themselves resources with varying quality. Population is the pivotal element in social studies. It is the point of reference from which all other elements are observed and from which they derive significance and meaning. 'Resources', 'calamities' and 'disasters' are all meaningful only in relation to human beings. Human beings are producers and consumers of earth's resources. Therefore, it is important to know how many people are there in a country, where do they live, how and why their numbers are increasing and what are their characteristics. The census of India provides us with information regarding the population of our country.We are primarily concerned with three major questions about the population:(i) Population size and distribution: How many people are there and where are they located?(ii) Population growth and processes of population change: How has the population grown and changed through time?(iii) Characteristics or qualities of the population: What are their age, sexcomposition, literacy levels, occupational structure and health conditions?POPULATION SIZE AND DISTRIBUTIONIndia's Population Size and Distribution by NumbersIndia's population as on March 2001 stood at 1,028 million, which account for 16.7 per cent of the world's population. These 1.02 billion people are unevenly distributed over our country's vast area of 3.28 million square km, which accounts for 2.4 per cent of the world's area. The 2001 Census data reveals that Uttar Pradesh with a population size of 166 million people is the most populous state of India. Uttar Pradesh accounts for about 16 per cent of the country's population. On the other hand, the Himalayan state Sikkim has a population of just about 0.5 million and Lakshadweep has only 60 thousand people. Almost half of India's population lives in just five states. These are Uttar Pradesh, Maharashtra, Bihar, West Bengal, and Andhra Pradesh. Rajasthan, the biggest state in terms of area, has only 5.5 per cent of the total population of India.India's share of Population & Area in the worldIndia's Population Distribution by DensityPopulation density provides a better picture of the uneven distribution. Population density is calculated as the number of persons per unit area. India is one of the most densely populated countries of the world. The population density of India in the year 2001 was 324 persons per sq km. Densities vary from 904 persons per sq km in West Bengal to only 13 persons per sq km in Arunachal Pradesh.POPULATION GROWTH AND PROCESSES OF POPULATION CHANGEPopulation is a dynamic phenomenon. The numbers, distribution and composition of the population are constantly changing. This is the influence of the interaction of the three processes, namely-births, deaths and migrations. Population GrowthGrowth of population refers to the change in the number of inhabitants of a country/territory during a specific period of time, say during the last ten years. Such a change can be expressed in two ways: in terms of absolute numbers and in terms of percentage change per year. The absolute numbers added each year or decade is the magnitude of increase. The rate or the pace of population increase is the other important aspect. It is studied in per cent per annum, e.g. a rate of increase of 2 per cent per annum means that in a given year, there was an increase of two persons for every 100 persons in the base population. This is referred to as the annual growth rate. India's population has been steadily increasing from 361 million in 1951 to 1028 million in 2001.The Magnitude and rate of India's Population growthProcesses of Population Change/GrowthThere are three main processes of change of population : birth rates, death rates and migration. The natural increase of population is the difference between birth rates and death rates.Birth rate is the number of live births per thousand persons in a year. It is a major component of growth because in India, birth rates have always been higher than death rates.Death rate is the number of deaths per thousand persons in a year. The main cause of the rate of growth of the Indian population has been the rapid decline in death rates. Till 1980, high birth rates and declining death rates led to a large difference between birth rates and death rates resulting in higher rates of population growth.The third component of population growth is migration.Migration is the movement of people across regions and territories. Migration can be internal (within the country) or international (between the countries). Internal migration does not change the size of the population, but influences the distribution of population within the nation. Migration plays a very significant role in changing the composition and distribution of population. In India, most migrations have been from rural to urban areas because of the "push" factor in rural areas. These are adverse conditions of poverty and unemployment in the rural areas and the "pull" of the city in terms of increased employment opportunities and better living conditions. Migration is an important determinant of population change. It changes not only the population size but also the population composition of urban and rural populations in terms of age and sex composition. In India, the rural-urban migration has resulted in a steady increase in the percentage of population in cities and towns. The urban population has increased from 17.29 per cent of the total population in 1951 to 27.78 per cent in 2001. There has been a significant increase in the number of 'million plus cities' from 23 to 35 in just one decade i.e. 1991 to 2001.Age CompositionThe age composition of a population refers to the number of people in different age groups in a country. It is one of the most basic characteristics of a population.The population of a nation is generally grouped into three broad categories:Children (generally below 15 years): They are economically unproductive and need to be provided with food, clothing, education and medical care.Working Age (15-59 years): They are economically productive and biologically reproductive. They comprise the working population.Aged (Above 59 years): They can be economically productive though they and may have retired. They may be working voluntarily but they are not available for employment through recruitment. The percentage of children and the aged affect the dependency ratio because these groups are not producers.Sex RatioSex ratio is defined as the number of females per 1000 males in the population. This information is an important social indicator to measure the extent of equality between males and females in a society at a given time. The sex ratio in the country has always remained unfavourable to females.Literacy RatesLiteracy is a very important quality of a population. Obviously, only an informed and educated citizen can make intelligent choices and undertake research and development projects. Low levels of literacy are a serious obstacle for economic improvement. According to the Census of 2001, a person aged 7 years. and above who can read and write with understanding in any language, is treated as literate.There has been a steady improvement in the literacy levels in India. The literacy rate in the country as per the Census of 2001 is 64.84 per cent; 75.26 per cent for males and 53.67 per cent for females.Occupational StructureThe percentage of population that is economically active is an important index of development. The distribution of the population according to different types of occupation is referred to as the occupational structure. An enormous variety of occupations are found in any country.Occupations are generally classified as primary, secondary, and tertiary.Primary activities include agriculture, animal husbandry, forestry, fishing, mining and quarrying etc.Secondary activities include manufacturing industry, building and construction work etc.Tertiary activities include transport, communications, commerce, administration and other services.The proportion of people working in different activities varies in developed and developing countries. Developed nations have a high proportion of people in secondary, and tertiary activities. Developing countries tend to have a higher proportion of their workforce engaged in primary activities. In India, about 64 per cent of the population is engaged only in agriculture. The proportion of population dependent on secondary and tertiary sectors is about 13 and 20 per cent respectively. There has been an occupational shift in favour of secondary and tertiary sectors because of growing industrialisation and urbanisation in recent times.HealthHealth is an important component of population composition, which affects the process of development. Sustained efforts of government programmes have registered significant improvements in the health conditions of the Indian population. Death rates have declined from 25 per 1000 population in 1951 to 8.1 per 1000 in 2001 and life expectancy at birth has increased from 36.7 years in 1951 to 64.6 years in 2001. The substantial improvement is the result of many factors including improvement in public health, prevention of infectious diseases and application of modern medical practices in diagnosis and treatment of ailments. Despite considerable achievements, the health situation is a matter of major concern for India. The per capita calorie consumption is much below the recommended levels and malnutrition afflicts a large percentage of our population. Safe drinking water and basic sanitation amenities are available to only onethird of the rural population. These problems need to be tackled through an appropriate population policy.Adolescent PopulationThe most significant feature of the Indian population is the size of its adolescent population. It constitutes one-fifth of the total population of India. Adolescents are generally grouped in the age-group of 10 to 19 years. They are the most important resource for the future. Nutrition requirements of adolescents are higher than those of a normal child or adult. Poor nutrition can lead to deficiency and stunted growth. But in India, the diet available to adolescents is inadequate in all nutrients.National Population PolicyRecognising that the planning of families would improve individual health and welfare, the Government of India initiated the comprehensive Family Planning Programme in 1952. The Family Welfare Programme has sought to promote responsible and planned parenthood on a voluntary basis. The National Population Policy 2000 is a culmination of years of planned efforts. The NPP 2000 provides a policy framework for imparting free and compulsory school education up to 14 years of age, reducing infant mortality rate to below 30 per 1000 live births, achieving universal immunisation of children against all vaccine preventable diseases, promoting delayed marriage for girls, and making family welfare a people-centered programme.NPP 2000 and AdolescentsNPP 2000 identified adolescents as one of the major sections of the population that need greater attention. Besides nutritional requirements, the policy put greater emphasis on other important needs of adolescents including protection from unwanted pregnancies and sexually transmitted diseases (STD). It called for programmes that aim towards encouraging delayed marriage and child-bearing, education of adolescents about the risks of unprotected sex, making contraceptive services accessible and affordable, providing food supplements, nutritional services, strengthening legal measures to prevent child marriage. People are the nation's most valuable resource. A well- educated healthy population provides potential power.Most populated state of India { give its reason also such as state bihar, tell population then illiteracy as reason }State with most and least of population with malesState with most and least of population with femalesState with most uneducated peoplereasons of unequal distribution of population in Indiareason for increase in birth rate and decrease in death ratemany other pnts can be covered, you can use old geography book of 9th class { last chapter } ( i dont know whether it's same or not )


Why do wetland birds have different bills?

what are the four major domains of the earth?Asked by ashu.shane...(student), on 15/2/11AnswersThe four major domains of the earth are1)atmosphere2)Biosphere3) Hdrosphere4) LithospherePosted by verma.kirti111(student), on 15/2/11The four major domains of the earth are1)Atmosphere(Gases)2)Biosphere(Living Beings)3) Hydrosphere(Water)4) Lithosphere(Land)If u fl my ansr s crrct tn gv me a thumpzz upPosted by sAnSkRuTiK(student), on 15/2/11Lithosphere(Land) Hydrosphere(Water) Atmosphere(Gases) Biosphere(CONNECTION OF LAND WATER AND AIRPosted by swayamshubham1...(student), on 10/3/12Lithosphere ( Land)Hydrosphere ( Water )Atmosphere ( Air )Biosphere ( The parts of the Earth where life is found , including land , water and the lower part of the atmosphere )Posted by ayshasamreen9...(student), on 10/3/12The four major domains of the earth are1)atmosphere2)Biosphere3) Hdrosphere4) LithospherePosted by jrathi03...(student), on 28/10/12hydrospherelithosphereatmospherebiosphere BiosphereThe biosphere is the space on or near Earth's surface that contains and supports living organisms. It is subdivided into the lithosphere, atmosphere, and hydrosphere. The lithosphere is Earth's surrounding layer, composed of solids such as soil and rock; it is about 80 to 100 kilometers (50 to 60 miles) thick. The atmosphere is the surrounding thin layer of gas. The hydrosphere refers to liquid environments such as lakes and oceans that lie between the lithosphere and atmosphere. The biosphere's creation and continuous existence results from chemical, biological, and physical processes.Requirements for lifeFor organisms to live, certain environmental conditions (such as proper temperature and moisture) must exist, and the organisms must be supplied with energy and nutrients (food). All the animal and mineral nutrients necessary for life are contained within Earth's biosphere. Nutrients contained in dead organisms or waste products of living cells are transformed back into compounds that other organisms can reuse as food. This recycling of nutrients is necessary because there is no source of food outside the biosphere. Words to KnowDecomposition: The breakdown of complex molecules---molecules of which dead organisms are composed---into simple nutrients that can be reutilized by living organisms. Energy: Power that can be used to perform work, such as solar energy.Global warming: Warming of the atmosphere that results from an increase in the concentration of gases that store heat, such as carbon dioxide.Nutrient: Molecules that organisms obtain from their environment; they are used for growth, energy, and various other cellular processes.Nutrient cycle: The cycling of biologically important elements from one molecular form to another and back to the original form.Photosynthesis: Process in which plants capture light energy from the Sun and use it to convert carbon dioxide and water into oxygen and organic molecules.Respiration: Chemical reaction between organic molecules and oxygen that produces carbon dioxide, water, and energy.Energy is needed for the functions that organisms perform, such as growth, movement, waste removal, and reproduction. It is the only requirement for life that is supplied from a source outside the biosphere. This energy is received from the Sun. Plants capture sunlight and use it to convert carbon dioxide and water into organic molecules, or food, in a process called photosynthesis. Plants and some microorganisms are the only organisms that can produce their own food. Other organisms, including humans, rely on plants for their energy needs.The major elements or chemical building blocks that make up all living organisms are carbon, oxygen, nitrogen, phosphorus, and sulfur. Organisms are able to acquire these elements only if they occur in usablechemical forms as nutrients. In a process called the nutrient cycle, the elements are transformed from one chemical form to another and then back to the original form. For example, carbon dioxide is removed from the air by plants and incorporated into organic compounds (such as carbohydrates) by photosynthesis. Carbon dioxide is returned to the atmosphere when plants and animals break down organic molecules (a process known as respiration) and when microorganisms break down wastes and tissue from dead organisms (a process known as decomposition).Evolution of the biosphereDuring Earth's long history, life-forms have drastically altered the chemical composition of the biosphere. At the same time, the biosphere's chemical composition has influenced which life-forms inhabit Earth. In the past, the rate at which nutrients were transformed from one chemical form to another did not always equal their transformation back to their original form. This has resulted in a change in the relative concentrations of chemicals such as carbon dioxide and oxygen in the biosphere. The decrease in carbon dioxide and increase in atmospheric oxygen that occurred over time was due to photosynthesis occurring at a faster rate than respiration. The carbon that was present in the atmosphere as carbon dioxide now lies in fossil fuel deposits and limestone rock. Scientists believe that the increase in atmospheric oxygen concentration influenced the evolution of life. It was not until oxygen reached high concentrations such as exist on Earth today that multicellular organisms like ourselves could have evolved. We require high oxygen concentrations to accommodate our high respiration rates and would not be able to survive had the biosphere not been altered by the organisms that came before us.Current developmentsMost research on the biosphere is to determine the effect that human activities have on the environment---especially on nutrient cycles. Application of fertilizers increases the amount of nitrogen, phosphorus, and other nutrients that organisms can use for growth. These excess nutrients damage lakes, causing overgrowth of algae and killing fish. Fuel consumption and land clearing increase carbon dioxide levels in the atmosphere and may cause global warming (a gradual increase in Earth's temperature) as a result of carbon dioxide's excellent ability to trap heat. Biosphere 2. Interest in long-term, manned space exploration has also generated research into the development of artificial biospheres. Extended missions into space require that nutrients be cycled in a volume no larger than a building. The Biosphere 2 Project, which received a great deal of popular attention in the early 1990s, provided insight into the difficulty of managing such small, artificial biospheres. The idea behind the project was to establish a planet in miniature where the inhabitants not only survived but learned to live cooperatively and happily together. This is quite revealing, given that human civilization has found it difficult to manage sustainably the much larger biosphere of planet Earth.Gaia HypothesisThe Gaia hypothesis (pronounced GAY-a), named for the Greek Earth goddess Gaea, is a recent and controversial theory that views Earth as an integrated, living organism rather than as a mere physical object in space. The Gaia hypothesis suggests that all organisms and their environments (making up the biosphere) work together to maintain physical and chemical conditions on Earth that promote and sustain life. According to the hypothesis, organisms interact with the environment as a homeostatic (balancing) mechanism for regulating such conditions as the concentrations of atmospheric oxygen and carbon dioxide. This system helps to maintain conditions within a range that is satisfactory for life. Although scientists agree that organisms and the environment have an influence on each other, there is little support within the scientific community for the notion that Earth is an integrated system capable of regulating conditions to sustain itself. The Gaia hypothesis is a useful concept, however, because it emphasizes the relationship between organisms and the environment and the effect that human activities have on them. One of the most spectacular structures ever built, Biosphere 2 is located in the Sonoran Desert at the foot of the Santa Catalina Mountains not far from Tucson, Arizona. It is the world's largest greenhouse, made of tubular steel and glass, covering an area of three football fields---137,416 square feet (12,766 square meters)---and rising to a height of 85 feet (26 meters) above the desert floor. Within the structure, there is a human habitat and a farm for the Biospherians or inhabitants to work to provide their own food. There are five other wild habitats or biomes representing a savannah, a rain forest, a marsh, a desert, and an ocean. Biosphere 2 is completely sealed so no air or moisture can flow in or out. Nearby are two balloon-like structures that operate like a pair of lungs for Biosphere 2 by maintaining air pressure inside. Only sunlight and electricity are provided from outside.On September 26, 1991, four women and four men from three different countries entered the Biosphere 2 and the doors were sealed for the two-year-long initial program of survival and experimentation. During this time, the Biospherians attempted to run the farm and grow their own food in the company of some pigs, goats, and many chickens. They shared the other biomes with over 3,800 species of animals and plants that were native to those habitats. The resident scientists observed the interactions of plants and animals, their reactions to change, and their unique methods of living. The Biospherians also had the assignment of experimenting with new methods of cleaning air and water.On September 26, 1993, the Biospherians emerged from Biosphere 2. It had been the longest period on record that humans had lived in an "isolated confined environment." Unfortunately, the experiment did not live up to expectations. The Biospherians experienced many difficulties, including an unusually cloudy year in the Arizona desert that stunted food crops, rapid growth and expansion of some ant species, and unusual behavior of bees fooled by the glass walls of the structure. In 1996, Columbia University took over operation of the facility, opening a visitors' center later that year. Biosphere 2 has been maintained for study but without human inhabitants. Its future remains uncertain.learn your textbooksTry it today.12MAJOR DOMAINS OF THE EARTHAs you have read in the first chapter, the earth is theonly planet which has life. Human beings can live herebecause the life sustaining elements of land, water andair are present on the earth.The surface of the earth is a complex zone in whichthree main components of the environment meet,overlap and interact. The solid portion of the earth onwhich we live is called the Lithosphere. The gaseouslayers that surround the earth, is the Atmosphere,where oxygen, nitrogen, carbondioxide and other gasesare found. Water covers a very big area of the earth'ssurface and this area is called the Hydrosphere. TheHydrosphere comprises water in all its forms, that is,ice, water and water vapour.The Biosphere is the narrow zone where we findland, water and air together, which contains all formsof life.LITHOSPHEREThe solid portion of the earth is called the Lithosphere.It comprises the rocks of the earth's crust and the thinlayers of soil that contain nutrient elements whichsustain organisms.There are two main divisions of the earth's surface.The large landmasses are known as the continentsand the huge water bodies are called the ocean basins.All the oceans of the world are connected with oneanother. Look at the map of the world (Figure 5.1). Areall the land masses connected with one another?The level of seawater remains the same everywhere.Elevation of land is measured from the level of the sea,which is taken as zero.5Word OriginIn Greek language,Lithos means Stone;Atmos means Vapour;Hudor means Water;and Bios means Life.Can you make words usingthe above?MAJOR DOMAINS OF THE EARTH 31Figure 5.1 : The World : Continents and Oceans32 THE EARTH : OUR HABITATThe highest mountain peak Mt. Everest is 8,848metres above the sea level. The greatest depth of 11,022metres is recorded at Mariana Trench in the PacificOcean. Could you imagine that depth of sea is muchmore than the highest point?ContinentsThere are seven major continents. These are separatedby large water bodies. These continents are -- Asia,Europe, Africa, North America, South America,Australia and Antarctica. Look at the map of the world(Figure 5.1) and notice that the greater part of the landmass lies in the Northern Hemisphere.Asia is the largest continent. It covers about onethirdof the total land area of the earth. The continentlies in the Eastern Hemisphere. The Tropic of Cancerpasses through this continent. Asia is separated fromEurope by the Ural mountains on the west (Figure5.1). The combined landmass of Europe and Asia iscalled the Eurasia (Europe + Asia).Europe is much smaller than Asia. The continentlies to the west of Asia. The Arctic Circle passes throughit. It is bound by water bodies on three sides. Look atthe map of the world and locate it.Africa is the second largest continent after Asia.The Equator or 00 latitude runs almost through themiddle of the continent. A large part of Africa lies inthe Northern Hemisphere. Look at the Figure 5.1; youwill find that it is the only continent through whichthe Tropic of Cancer, the Equator and the Tropic ofCapricorn pass.The Sahara Desert, the world's largest hot desert,is located in Africa. The continent is bound on all sidesby oceans and seas. Look at the world map (Figure 5.1).You will notice that the world's longest river the Nile,flows through Africa. Notice where the Equator, theTropic of Cancer and the Tropic of Capricorn pass inthe map of Africa.North America is the third largest continent of theworld. It is linked to South America by a very narrowstrip of land called the Isthmus of Panama. Thecontinent lies completely in the Northern and WesternHemisphere. Three oceans surround this continent.Can you name these oceans?Do you know?Edmund Hillary(Britain) andTenzing Norgay Sherpa(India) were the first mento climb the highestmountain peak Mt. Evereston the planet earth on 29thMay, 1953.Junko Tabei (Japan)was the first woman toreach the summit on 16thMay, 1975. The firstIndian woman to climb thehighest peak on 23rd May,1984 was Bachendri Pal.MAJOR DOMAINS OF THE EARTH 33South America liesmostly in the SouthernHemisphere. Which twooceans surround it onthe east and the west?The Andes, world'slongest mountainrange, runs through itslength from north tosouth (Figure 5.1).South America has theworld's largest river, theAmazon.Australia is thesmallest continent thatlies entirely in theSouthern Hemisphere.It is surrounded on allsides by the oceans andseas. It is called anisland continent.Antarctica, completely in the Southern Hemisphere,is a huge continent. It is larger than the combinedarea of Europe and Australia. The South Pole liesalmost at the centre of this continent. As it is locatedin the South Polar Region, it is permanently coveredwith thick ice sheets. There are no permanent humansettlements. Many countries have research stations inAntarctica. India also has research stations there. Theseare named as Maitri and Dakshin Gangotri.HYDROSPHEREThe earth is called the blue planet. More than 71 percent of the earth is covered with water and 29 per centis with land. Hydrosphere consists of water in all itsforms. As running water in oceans and rivers and inlakes, ice in glaciers, underground water and the watervapour in atmosphere, all comprise the hydrosphere.More than 97% of the Earth's water is found in theoceans and is too salty for human use. A largeproportion of the rest of the water is in the form oficesheets and glaciers or under the ground and a verysmall percentage is available as fresh water for humanFigure 5.2 : Isthmus and StraitName the Straitbetween Indiaand Sri Lanka.34 THE EARTH : OUR HABITATOceansOceans are the major part of hydrosphere. They areall interconnected.The ocean waters are always moving. The three chiefmovements of ocean waters are the waves, the tidesand the ocean currents. The four major oceans are thePacific Ocean, the Atlantic Ocean, the Indian Ocean andthe Arctic Ocean, in order of their size (Figure 5.1).The Pacific Ocean is the largest ocean. It is spreadover one-third of the earth. Mariana Trench, thedeepest part of the earth, lies under the Pacific Ocean.The Pacific Ocean is circular in shape. Asia, Australia,Figure 5.3 : Comparative size of the continentsCount the squares given in Figure 5.3 and answer the following :(a) Name the largest and smallest continents; (b) Which is larger -- North or South America?use. Hence, despite being a 'blue planet' we facea shortage of water!!MAJOR DOMAINS OF THE EARTH 35North and South Americas surround it. Look at themap and find out the location of the continents aroundthe Pacific Ocean.The Atlantic Ocean is the second largest Ocean inthe world. It is 'S' shaped. It is flanked by the Northand South Americas on the western side, and Europeand Africa on the eastern side. The coastline of AtlanticOcean is highly indented. This irregular and indentedcoastline provides ideal location for natural harboursand ports. From the point of view of commerce, it isthe busiest Ocean.The Indian Ocean is the only ocean named after acountry, that is, India. The shape of ocean is almosttriangular. In the north, it is bound by Asia, in thewest by Africa and in the east by Australia.The Arctic Ocean is located within the Arctic Circleand surrounds the North Pole. It is connected with thePacific Ocean by a narrow stretch of shallow waterknown as Berring strait. It is bound by northern coastsof North America and Eurasia.ATMOSPHEREThe earth is surrounded by a layer of gas called theatmosphere. This thin blanket of air is an integraland important aspect of the planet. It provides us withthe air we breathe and protects us from the harmfuleffects of sun's rays.The atmosphere extends up to a height of about1,600 kilometres. The atmosphere is divided into fivelayers based on composition, temperature and otherproperties. These layers starting from earth's surfaceare called the troposphere, the stratosphere, themesosphere, the thermosphere and the exosphere.The atmosphere is composed mainly of nitrogen andoxygen, which make up about 99 per cent of clean,dry air. Nitrogen 78 per cent, oxygen 21 per cent andother gases like carbondioxide, argon and otherscomprise 1 per cent by volume. Oxygen is the breathof life while nitrogen helps in the growth of livingorganisms. Carbon dioxide, though present in minuteamount, is important as it absorbs heat radiated bythe earth, thereby keeping the planet warm. It is alsoessential for the growth of plants.The density of the atmosphere varies with height. It Figure 5.4 : Layers of the AtmosphereExosphere36 THE EARTH : OUR HABITATis maximum at the sea level anddecreases rapidly as we go up. Youknow, the climbers experienceproblems in breathing due to thisdecrease in the density of air. Theyhave to carry with them oxygencylinders to be able to breathe athigh altitudes. The temperature alsodecreases as we go upwards. Theatmosphere exerts pressure on theearth. This varies from place to place.Some areas experience high pressureand some areas low pressure. Airmoves from high pressure to low pressure. Moving airis known as wind.BIOSPHERE -- THE DOMAIN OF LIFEThe biosphere is the narrow zone of contact betweenthe land, water and air. It is in this zone that life, thatis unique to this planet, exists. There are severalFigure 5.6 : The BiosphereFigure 5.5 : A mountaineerMAJOR DOMAINS OF THE EARTH 371. Answer the following questions briefly.(a) What are the four major domains of the earth?(b) Name the major continents of the earth.(c) Name the two continents that lie entirely in the Southern Hemisphere.(d) Name the different layers of atmosphere.(e) Why is the earth called the 'blue planet'?(f) Why is the Northern Hemisphere called the Land Hemisphere?(g) Why is the Biosphere important for living organisms?species of organisms that vary in size from microbesand bacteria to huge mammals. All the livingorganisms including humans are linked to each otherand to the biosphere for survival.The organisms in the biosphere may broadly bedivided into the plant kingdom and the animalkingdom. The three domains of the earth interact witheach other and affect each other in some way or theother. For example, cutting of forests for fulfilling ourneeds of wood, or clearing land for agriculture maylead to fast removal of soil from slopes. Similarly earth'ssurface may be changed due to natural calamities likeearthquakes. For example, there could be submergenceof land, as happened in the case of Tsunami recently.Parts of Andaman & Nicobar islands were submergedunder water. Discharge of waste material into lakesand rivers makes the water unsuitable for human use.It also damages other forms of life.Emission from industries, thermal power plantsand vehicles, pollute the air. Carbon dioxide (CO2) isan important constituent of air. But increase in theamount of CO2 leads to increase in global temperatures.This is termed as global warming. There is thus, aneed to limit the use of resources of the earth tomaintain the balance of nature between the domainsof the lithosphere, the atmosphere and thehydrosphere.38 THE EARTH : OUR HABITAT2. Tick the correct answers.(a) The mountain range that separates Europe from Asia is(i) the Andes (ii) the Himalayas (iii) the Urals(b) The continent of North America is linked to South America by(i) Isthmus (ii) Strait (iii) Canal(c) The major constituent of atmosphere by per cent is(i) Nitrogen (ii) Oxygen (iii) Carbon dioxide(d) The domain of the earth consisting of solid rocks is(i) the Atmosphere (ii) the Hydrosphere (iii) the Lithosphere(e) Which is the largest continent?(i) Africa (ii) Asia (iii) Australia3. Fill in the blanks.(a) The deepest point on the earth is _____________ in the Pacific Ocean.(b) The _____________ Ocean is named after a country.(c) The _____________ is a narrow contact zone of land, water and air thatsupports life.(d) The continents of Europe and Asia together are known as _____________.(e) The highest mountain peak on the earth is _____________.1. Cut the outline of the continents from an outline map of the world andarrange them according to their decreasing sizes.2. Cut the outline of the continents from an outline map of the world and tryto fit them together as a Jig-saw puzzle.3. Collect pictures of expeditions to the Himalayas. Write about the kind ofequipment carried by the climbers for protection against sunshine,temperature and the lack of air.Map Skills1. On the outline map of the world, mark the following :Europe, Asia, Antarctica, South America, Australia, Indian Ocean, PacificOcean, Atlantic Ocean, Ural Mountains and Isthmus of Panama.