Introduction to the spheres of the earth - class-X

About 3.8 billion years ago after the formation of earth, single celled prokaryotic cells (bacteria) appeared. It is supposed that the multicellular living organisms evolved from them. So, the correct option is B.

The Ozone layer is located in the stratosphere in a region that is 10 to 50 km above the Earth.

The atmosphere is divided into layers separated by transition zones called pauses. The stratopause is the boundary layer that separates the stratosphere from the mesosphere above it.

The ozone layer filters out most of the sun's harmful ultraviolet radiation and is thereby significant for the life on Earth.

Ozone in the troposphere is considered a pollutant. Its background concentration is typically very low, generally around 0.05 ppm in clean air environments.

The troposphere is the lowest layer of Earth's atmosphere. It is the layer closest to the ground where weather phenomena occur.

Humans are considered the dominant species in the biosphere primarily due to their advanced cognitive abilities. This brain power allows for complex problem-solving, tool creation, and environmental adaptation.

The Nilgiri Biosphere Reserve, established in 1986, was the first biosphere reserve in India. It is located in the Western Ghats and encompasses parts of Tamil Nadu, Kerala, and Karnataka.

The global environment is generally categorized into the atmosphere (air), hydrosphere (water), and biosphere (living organisms). These three components interact to support life on Earth.

The lithosphere is the rigid, outermost shell of the Earth. It includes the crust and the uppermost part of the mantle, making it the most solid and rigid layer.

Topography is a field of geoscience and planetary science comprising the study of surface shape and features of the Earth and other observable astronomical objects including planets, moons, and asteroids. 

The ozone layer is present in the stratosphere above the Earth. The layer is present at a distance of about 20-30 km away from the surface of the Earth. The layer of ozone is responsible for the absorption of the harmful Ultraviolet radiations from the solar radiations. These radiations are prevented from entering the Earth's atmosphere to prevent the development of skin cancer

• The ozone layer or ozone shield is a region of Earth's stratosphere which contains a high concentration of ozone ($O _3$) in relation to other parts of the atmosphere,
  
• The ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (UVR) from the sun, protecting life on Earth from its potentially harmful effects.
• Hence Ozone shields the earth from the harmful ultraviolet rays from the sun.
• So, the correct answer is 'Sun'.

The layer of the atmosphere closest to the earth is the troposphere also known as the lower atmosphere fixed composition of various constituents of air namely the carbon dioxide, nitrogen, ozone, rare gases etc, but the amount of water vapour varies from place to place and from time to time.

The lithosphere is defined as the rigid outer layer of the Earth, consisting of the crust and the uppermost solid part of the mantle. It is distinct from the deeper, more fluid layers like the core.

In the stratosphere, ozone molecules (three oxygen atoms) bonded together, prevent some of the Sun's most intense rays from reaching the Earth's surface. Currently, scientists and researchers worldwide are monitoring this layer; so thin at the South Pole, we call it a hole where the molecules are being very less.

Air is a bad conductor of heat and not a good conductor hence the temperature on the earth is maintained for life to exist unlike the other planets. Atmosphere prevents sudden increase in temperature during the day light hours. It slows down the escape of heat into outer space during the night.

The earth that we live on is one of the planets of the solar system. Its crust is deep and we stay on its uppermost layer. The upper layer of earth is formed by soil. It can get weathered away due to external forces like water, wind etc.

The lithosphere is referred to the solid part of the Earth. This is the part which includes the crust and the upper mantle. There are two types of the lithosphere. The oceanic lithosphere is the part which is comprised of the oceans. The continental lithosphere is the part which is comprised of the continental crust. The continental part comprises of a more thick layer.

The thermosphere is located above the mesosphere. Because it has very low air density and lacks significant water vapor, it is essentially cloudless.

The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The troposphere is the lowest portion of Earth's atmosphere. It contains approximately 80% of the atmosphere's mass. 

An envelope of gas that surrounds earth is called atmosphere. It contains 78% nitrogen, 21% oxygen, 0.03% carbon dioxide, 0.9% argon and traces of other gases like helium, little amount of water vapour, dust particles and other solid particles. So, the correct option is D. 

Meteors enter the Earth's atmosphere at high speeds and encounter enough friction in the mesosphere to heat up and burn, creating the phenomenon known as shooting stars.

The hydrosphere, specifically the world's oceans, plays a critical role in regulating Earth's temperature by absorbing and distributing solar heat through ocean currents and evaporation.

Pedogenesis is the process of soil formation. Since soil is a component of the Earth's crust, this process occurs within the lithosphere.

The troposphere is the lowest layer of the atmosphere where almost all weather phenomena, including thunderstorms, rain, and clouds, occur due to the presence of water vapor and convection.

Scientific consensus suggests that life on Earth originated in the oceans (hydrosphere), where early chemical reactions in a 'primordial soup' led to the development of the first simple organisms.

Approximately 97.5% of Earth's water is saline (oceans), while only about 2.5% is freshwater, much of which is locked in glaciers and ice caps.

Artificial satellites orbit the Earth in the thermosphere and exosphere. Among the choices provided, the thermosphere is the correct region where many low Earth orbit satellites are located.

Earth is the only known planet where various forms of life like, plants, animals etc. are present. It makes earth unique from other planets. So, the correct option is A.

The faint band of stars seen across the night sky is the view of the Milky Way's galactic disc from our perspective inside the galaxy.

While estimates vary, current astronomical models often cite approximately 100 billion (1,00,000 million) galaxies in the observable universe.

Stars twinkle because their light is refracted by Earth's atmosphere. Planets, being closer, appear as discs rather than point sources, so their light is less affected by atmospheric turbulence, making them appear to glow steadily.

The solar system consists of eight recognized planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was reclassified as a dwarf planet in 2006.

Approximately 2000-2500 stars are visible to the naked eye under ideal dark sky conditions. This number represents stars with apparent magnitude brighter than about 6.

The biosphere is the global sum of all ecosystems, representing the zone of life on Earth. It includes all living organisms and their interactions with the lithosphere, hydrosphere, and atmosphere.

Man and biosphere programme is an international biological programme of UNESCO (United Nations Educational Scientific and Cultural Organization) which was started in 1971 but was introduced in India in 1986.

During the Hadean Eon, the early Earth was extremely hot due to frequent collisions, radioactive decay, and gravitational contraction. Estimates for the surface temperature during this formation period are typically in the range of 5000 to 6000 degrees Celsius.

Ozone in the stratosphere absorbs ultraviolet radiation from the sun, which converts that energy into heat. This process makes the stratosphere warmer by approximately 53 degrees Celsius compared to the temperature at the tropopause.

The Earth is differentiated into the crust, mantle, and core. The crust is the outermost, thin, solid layer of the planet.

The terrestrial planets are the four inner planets of the solar system: Mercury, Venus, Earth, and Mars. They are characterized by their solid, rocky surfaces.

Hydrogen is the most abundant element in the Sun, making up about 73% of its mass. Helium is second at about 25%, with other elements like carbon and oxygen being trace components.

The primary atmosphere of the early Earth was reducing, meaning it contained hydrogen-rich gases like methane and ammonia, and lacked free oxygen.

As the Earth cooled and the atmosphere evolved, atomic gases (which were unstable) and free oxygen (which was highly reactive) were largely absent or consumed in chemical reactions. Both are considered to have been absent or disappeared during the transition.

Cyanobacteria, also known as blue-green algae, were the first organisms to perform oxygenic photosynthesis. This process released oxygen as a byproduct, eventually leading to the Great Oxidation Event.

In the extremely hot, early stages of Earth, the atmosphere consisted of simple atoms like hydrogen, carbon, oxygen, and nitrogen, which had not yet formed complex stable molecules due to the intense thermal energy.

The Oparin-Haldane hypothesis suggests the primary atmosphere was composed of methane (CH4), ammonia (NH3), hydrogen (H2), and water vapor (H2O). These were the precursors for organic molecules.

In the mesosphere, the temperature decreases with altitude because there are very few molecules to absorb solar radiation. It drops from approximately -2 degrees Celsius at the stratopause to about -92 degrees Celsius at the mesopause.

Primordial soup refers to the hypothetical solution of organic compounds in the early Earth's oceans, which provided the environment for the synthesis of life's building blocks.

The consensus in evolutionary biology is that the first life forms, or cell-like structures, originated in the oceans, where water provided protection from UV radiation and a medium for chemical reactions.

The ozonosphere (ozone layer) in the stratosphere protects life from harmful UV radiation. The thermosphere also absorbs high-energy X-rays and gamma rays, providing additional protection. Both layers contribute to shielding Earth from dangerous solar and cosmic radiation.

Microspheres (or proteinoid microspheres) are abiotic structures that exhibit properties like growth, division, and the ability to maintain internal chemistry, which are precursors to cellular life.

As free oxygen began to accumulate in the atmosphere due to photosynthesis, methane was oxidized into carbon dioxide and water, leading to its disappearance from the atmosphere.

The asthenosphere is a semi-plastic layer of the upper mantle located beneath the lithosphere, typically extending from about 70 km to 280 km in depth.

The asthenosphere is the highly viscous, mechanically weak, and ductile region of the upper mantle of the Earth.

The ionosphere is an ionized region of the upper atmosphere that overlaps with the mesosphere and thermosphere, typically situated between them.

The primitive atmosphere is widely accepted to have contained water vapor, hydrogen, ammonia, and methane, which provided the raw materials for organic synthesis.

The ionosphere is not another atmospheric layer. It occupies the same region of the upper atmosphere as the thermosphere. In this region of the atmosphere the Sun's energy is so strong that it breaks apart molecules and atoms of air, leaving ions. So the correct answer is 'Thermosphere'.

Troposphere is the layer where all weather occurs. this is the lowest layer.

In the thermosphere, temperatures increase significantly with altitude due to the absorption of high-energy solar radiation, reaching temperatures up to 1500 degrees Celsius or more.

Troposphere is the lowest layer in the earth's atmosphere. it is the same layer in which all the change in weather takes place. Lapse rate is the rate at which the temperature drops due to the difference in elevation. the more the altitude the more the drop in temperature is there. The lapse rate of $6.5$ is there for the level of $0$ to  $11,000$ m. This is the region in which troposphere lies. 

The Ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains high concentrations of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. As the ozonosphere only contains high levels of ozone gas, therefore all the other things such as the dust particles. water vapours and CO2 are absent from it. 

The troposphere is the lowest layer of the atmosphere. Its thickness varies by latitude, being thickest at the equator (about 16-18 km) and thinnest at the poles (about 8 km).

The thermosphere contains the ionosphere, which reflects radio waves back toward Earth and enables long-distance telecommunications and broadcasting. The other layers do not possess this key radio-wave reflecting property to the same extent.

Ozone is concentrated mainly in the stratosphere, where it absorbs solar radiation, protecting Earth's living organisms from the ultraviolet light from the sun. UV radiation is harmful to DNA; without the atmosphere's ozone, living organisms could not exist and thrive as they do now. The area in which ozone is concentrated in stratosphere is called the ozonosphere, So the correct answer is 'Both B and C'.

Most of the sun's UV-B radiation is absorbed by ozone in the stratosphere. UV-C radiation is absorbed by oxygen and ozone in the stratosphere and never reaches the Earth's surface. This is good because the C type rays are the most damaging of all. So the correct answer is 'Complete UV-C and a large amount of UV-B '

The ozone layer in the stratosphere absorbs the majority of the sun's harmful ultraviolet (UV) radiation, protecting living organisms from DNA damage and skin cancer.

The ozone layer is located within the stratosphere, specifically in the lower portion of the stratosphere, at an altitude of approximately 15 to 35 kilometers.

The ozone layer is a region of the Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation.

The stratosphere is the second layer of the atmosphere. At the equator, it is at the height of 20 km and at poles at 7 km. The stratosphere shows the presence of the ozone layer that has formed due to the reaction of the UV rays with the atmosphere. The ozone so formed in capable of absorbing the UV rays emanating from the sun, including the UV-B which is the most harmful. Due to this absorption, the stratosphere shows the stratification of temperature. The temperature is more towards the upper layers of the atmosphere and less towards the troposphere. 

The tropopause is the boundary in the Earth's atmosphere between the troposphere and the stratosphere. Therefore it would serve as the upper part of the troposphere. So the correct answer is ' Upper part of troposphere'. 

Location in Earth's atmosphere. In the midlatitudes, the peak concentrations of ozone occur at altitudes from 20 to 25 km (about 12 to 16 miles). Most of the remaining ozone occurs in the troposphere, the layer of the atmosphere that extends from Earth's surface up to the stratosphere. The Ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million

If there were no atmosphere around the earth, the temperature of the earth will increase during day and decrease during night. In the absence of atmosphere around the earth, it will be like a moon. There would be no life, no winds, no rains, no fires, no protection against harmful solar radiations. Due to absence of atmosphere around the moon, the temperature ranges from -190$^0$C to 110$^0$C. Air is a bad conductor of heat. The atmosphere has an average temperature of the earth almost steady during the day and night. It prevents sudden increase in temperature during the day time. Also, it decreases the rate of escape of heat during night time.

The ozone layer was discovered by Charles Fabry and Henri Buisson in 1913. The depletion of ozone was discovered by Farman, Gardiner and Shanklin in 1985.

The ozone layer resides within the stratosphere, specifically in the lower portion of it between roughly 15 and 35 kilometers above Earth's surface. It plays a critical role in absorbing harmful ultraviolet radiation from the sun.

Weather is the state of the atmosphere which can change on a daily basis. It describes the degree to which it is hot or cold , humid or dry, calm or stormy etc. therefore, it cannot be the seasonal change in the atmosphere as that would mean changing of seasons. It cannot be average variation of atmospheric conditions as that would be climate change. It cannot be all of the above because two options indicate season and
climate. So the correct answer is 'Short term properties of
atmosphere.'

Carbon dioxide is a colourless gas with a density of about 60% higher than that of dry air. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms. It occurs naturally in Earth's atmosphere as a trace gas. The current concentration is about 0.04% (410 ppm) by volume, having risen from pre-industrial levels of 280 ppm. Carbon dioxide is odourless at normally encountered concentrations. However, at high concentrations, it has a sharp and acidic odour.

Life is not possible without a stable atmosphere containing the right chemical ingredients for living organisms: hydrogen, oxygen, nitrogen, and carbon. These ingredients must be balanced. Therefore we need carbon dioxide, ozone as well as water vapours. These are present in minute quantities but are essential for life. So the correct answer is ' Carbon dioxide, ozone and water vapours'.

The absorption of ultraviolet radiation by ozone molecules in the stratosphere releases heat, which causes the temperature in the stratosphere to increase with altitude, making it warmer than it would be otherwise.

The resources can be divided into 5 types based on the resources of earth. These are Tej, Marut, Ap, Khsiti and Vyom. Tej is a basic resource from sun. Marut is basic resource from wind. Ap is basic resource from water. Khsiti is basic resource of earth. It represents air. Vyom is the basic resource of explorating space.

Temperatures in the mesosphere decrease with altitude. Because there are few gas molecules in the mesosphere to absorb the Sun’s radiation, the heat source is the stratosphere below. The mesosphere is extremely cold, especially at its top, about -90 degree Celsius.  So the correct answer is ' it decreases from -2 to -92 degrees. '

The UV-A radiations are scattered and reach the surface of the earth continually. These are the least harmful radiations. The UV-B and UV-C are the most harmful radiations are capable of burning the human skin within 15 minutes of the exposure. These are absorbed by the ozone layer in the stratosphere. The ozone depletion results in the exposure of the earth surface to the UV-B and UV-C causing immunity problems, skin cancers, chlorophyll bleaching etc.

The temperature at the tropopause, which is the upper boundary of the troposphere, is generally around -50 to -60 degrees Celsius.

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.

The ozone layer (ozonosphere) is generally found at altitudes of 15-35 km. The options provided are confusingly phrased regarding poles versus equator, but 12-20 km is a common range for the lower boundary of the ozone layer.

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.