1) Why is the atmosphere essential for life?
ANSWER:-The atmosphere is essential for life because it maintains
an appropriate climate for the sustenance of life by carrying out the following
a) It prevents a sudden increase
in temperature during
day time.
b) It also slows down the escape of heat from the surface of the
Earth into outer space during night time.
2) Why is water essential for life?
ANSWER:-Water is essential for life because transportation of
biological substances needs water as medium, without water there would be no
vegetation on earth
3) How are living organisms dependent on the soil? Are organisms that live in water
totally independent of soil as a
ANSWER:-Almost all living organisms are dependent on soil. Some
depend directly, while some depend indirectly.
Plants need soil for getting support
as well as nutrients to
prepare their food. On
the other hand, organisms depend on plants for food and other substances that
are essential for life.
Organisms that live in water are not totally independent of soil
as a resource. These organisms depend on aquatic plants for food and other
4) You have seen weather reports on television and in
newspapers. How do you think we are able to predict the weather?
ANSWER:-The meteorological department of the government collects
data on the elements of
weather such as maximum
minimum temperatures, maximum and
humidity, rainfall, wind
speed, etc. They are able to study
elements using various
instruments. The maximum and minimum temperature of a day
is measured by a
thermometer known as the maximum-minimum thermometer. Rain fall is measured by an instrument known
as the rain gauge. Wind
speed is measured by anemometers.
5) Write a note on how forests
influence the quality of our air,
soil and water resources.
ANSWER:-Forests influence the quality of our air, soil, and water
resources in various ways. Some of them are:
(i) Forests balance the percentages of carbon dioxide and oxygen
in the atmosphere. The increasing amount of carbon dioxide caused by human
activities is balanced by a larger intake of carbon dioxide by plants during
the process of
Simultaneously, a large amount of oxygen is released.
(ii) Forests prevent soil erosion. Roots of plants bind the soil
tightly in a way that the surface of
soil cannot be eroded away by wind, water, etc.
(iii) Forests help in the replenishment of water resources. During
the process of transpiration, a huge amount of water vapour goes into the air
and condenses to form clouds. These clouds cause rainfall that
recharge water bodies.
6) We know that many human activities lead to increasing levels
of pollution of the air, water-
and soil. Do you think that isolating these activities to specific and limited
areas would
in reducing pollution?
ANSWER:-Yes. Isolating human activities to specific areas would help in reducing levels of pollution.