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earth constitutes the hydrosphere . It includes Biosphere
water bodies like oceans, seas, rivers, lakes etc. Biosphere is the narrow contact zone consisting of
More than 71% of the earth’s surface is covered the lower part of the atmosphere, the upper part of
with water. So, the earth is sometimes called
the lithosphere and a part of hydrosphere where
watery planet . Moreover, the earth is the only all forms of life are found. It makes the earth a
planet which has water.
unique planet in the solar system because it
Water is essential for all sorts of life. We need supports life. It includes all the living components
water for domestic use, farmers need water for of environment like plants, animals, insects,
their crops and industries need water for microorganisms and human beings.
manufacturing. It provides a habitat to the marine
life and food in the form of fish, shrimps, crabs Info Bits
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etc. Even in the seabed, deposits of mineral oil
and gas are found. Oceans are major links The study of the relationships between living
between landmasses, and hence promote trade organisms and their surroundings is called ecology.
and culture. It helps us to understand how different kinds of
life forms depend upon non-living things, and are
Atmosphere
influenced by their interaction with their
The blanket of air surrounding the earth is known environment.
as the atmosphere . It is a mixture of gases, dust
and water vapour. The atmosphere extends to Quiz Time
about 1600 km from the surface of the earth. The Fill in the blanks :
force of gravity exerted by the earth holds the 1. The environment has two components
atmosphere around it. __________ and __________ .
Oxygen, a life giving gas present in the 2. __________ environment comprises air, water,
atmosphere is 21% by volume. It is essential for land and food.
all living beings to breathe. Other gases present in
3. __________ is the solid outer covering of the
the atmosphere are carbon dioxide (0.03%) which
earth’s surface consisting of rocks and soils.
is needed by plants to prepare food and nitrogen
(78%) which is also used by plants indirectly for 4. The ozone layer contains high concentration of
__________ gas.
their growth. Also, there are traces of other gases
in atmosphere like argon, neon, helium and 5. __________ makes the earth a unique planet in
methane. the solar system.
Atmosphere is very important for all living beings. HUMAN ENVIRONMENT
Change in atmosphere produces change in the
weather and climate. It protects us from the Man is a part of the environment. He adapts
harmful ultraviolet rays. It also prevents earth from himself or modifies the environment where he
becoming extremely hot and cold. lives to a great extent to suit his needs. With the
help of technology he learnt to grow crops, to
domesticate animals and started living a settled
Info Bits life in villages. Then trade and commerce,
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industrial and efficient means of transport and
The ozone layer is a layer in the earth’s atmosphere communication developed. Gradually, human
which contains high concentration of ozone (O ) beings used their skills and created things from the
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gas. This layer absorbs 93.99% of the sun’s high natural environment, so as to satisfy their needs,
frequency ultraviolet rays, which are potentially wants and aspirations. Thus, human environment
dangerous to life on earth. includes everything created by man with the help
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