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Global Warming
Carbon dioxide present in air balances the temperature of the earth. The heat
radiations of the sun absorbed by earth are when escaped from the earth, the carbon
dioxide gas in atmosphere prevents it from escaping and keeps the earth warm. This is
called greenhouse effect. But due to the increasing of the green house gases the
temperature of the earth has increased, which is called global warming. Air pollution
is the main reason of global warming. Due to global warming, glacier at mountains

Hole in Ozone Layer
 There is a layer of ozone gas in atmosphere which prevents harmful rays of sun

entering the earth. Due to the increasing air pollution there became a hole in ozone
layer over Antarctica.
 Through the ozone hole harmful rays of the sun can reach the earth which may cause
skin cancer and several other diseases to mankind and other living beings.

Discuss in the class about what problems the environment faces every day and how we can
help.

Let’s
Revise

 When we talk about our environment we mean everything in the world around us which
can affect our lives.

 Five basic needs of human beings from the environment are oxygen, water, food, shelter
and warmth.

 Humans have caused so many changes that many living things cannot get what they
need.

Points to Remember

Pollution : the substance into the environment which are harmful for living things
Wildlife : The environment where animals and plants are present

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