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3.  Is the action of preserving the
environment
 Synonims : protection,
maintenance, security
 keep from being damaged or
destroyed.

4.  Is the action of conserving the
environment
 Synonims: save keeping,
guarding, care
 protect and nurture.

5.  human beings use water and coal to produce electricity
which in turn helps us to provide heat and light for our
homes.
 Trees should be allowed to grow. They help in reducing air
temperature, remove pollutants from the atmosphere,
provide us with oxygen, reduce noise pollution and most
important, decrease soil erosion. Some times it becomes
necessary to cut down trees. This should be made up by
planting more trees.