[Old] Social science 4 Marks Each

Mountains :

• Mountains obstruct moisture bearing winds and bring rainfall to one side while the other side gets less rainfall.
• Mountains are homes to beautiful hill stations that are places of tourist interest .
• Rivers originating from mountains from fertile plains, and also provide fresh water to us.

Fields :

• Various crops like grains , cash crops , oil seeds etc. are cultivated in various kinds of fields .
• Fertile fields provide mankind with food that s very necessary to sustain life .

Rivers :

• Rivers are like our mothers . They provide water for drinking as well as for irrigation . fresh water of rivers is useful in many ways.

Lakes :

• Lakes and pond supply water for drinking as well as for irrigation . Larger reservoirs are also useful as transport routes.

Forests .:

• Forests prevents the climate from becoming dry and unfavourable .Forests keep the weather cool and help to bring rains.
• Forests obstruct winds and thus protect crops as well as arrest the growth of deserts .
• Wood available from forests is used for building , houses making furniture and fuel.
• Forests provides raw material for many industries.

The sphere of air that wraps the Earth from all sides is called “ Atmosphere “

• It extends up to about 1600 km from the surface of the Earth and it cannot bee seen clearly with thw naked eye .
• Uses of Atmosphere :
• Oxygen in the atmosphere is essential to all living organisms on the earth .
• Nitrogen is necessary for the growth of vegetation.
• Carbon dioxide is the food for green vegetation.
• Nitrogen reduces the intensity of oxygen.
• Ozone gas absorbs the ultra-violet sunrays and thus protects the earth from the intense heat of the sun.
• Ozone also an invigorating gas .
• The dust particles in the atmosphere help to spread sunrays in all directions.
• So there is neither sudden light after sunrise nor sudden darkness after sunset.
• Dust particles refflect sunrays which help us to receive sunlight. This particles also help to from clouds .
• We can hear sound only due to the atmosphere . Radio broadcasts and television are possible only due to the presense of atmosphere.

All the four spheres on Earth , I,e. lithosphere ,hydrosphere ,atmosphere and biosphere are interrelated very closely.

• Due to the collective impact of all these spheres conditions favourable for life have devloped on Earth.
• Lithosphere is useful in many ways .
• It is the home of mankind.
• It gives space for constructing homes, obtaining fresh water and land for cultivation as well as forests and useful minerals for industries .
• Hydrosphere provides fresh water to all living organism.
• Atmosphere provides life giving oxygen to all living organisms.
• No life from can survive without air and water.
• That part of the lithosphere , Hydrosphere and atmosphere where the living world exists is called “ Biosphere”
• This is one of the important spheres on Earth as this is the only planet in the solar system that has the biosphere .
• Thus all four spheres are interrelated.