Short Questions: Major Domains of the Earth | NCERT Summary: UPSC PDF Download

Q1: What are the life sustaining elements present on the earth?
Ans:

• The earth is the only planet of the Solar System which has life.
• It is the home of mankind.
• The life sustaining elements are land, water and air that are present on the earth.

Q2: Define atmosphere. What is its importance to us?
Ans:

• The earth is surrounded by an envelope of air.
• It is called atmosphere.
• This thin blanket of air is an integral and the most important aspect of the planet. It is very important to us as it enables us to breathe and protects us from the harmful effects of the sun’s rays.

Q3: Describe the density of the atmosphere.
Ans: The density of the atmosphere varies with height.

• It is the highest at sea level.
• It decreases rapidly with increase in height.
• Climbers experience problems in breathing due to decrease in density.
• Temperature also decreases with increase in height.

Q4: What is the biosphere? Give its major features.
Ans: Biosphere

• The biosphere is the narrow zone of contact between the land, water and air, comprising all forms of life.

Features:

• There are several species of organism in the biosphere.
• They vary in size from microbes and bacteria to huge mammals.
• All the living organisms including human are linked to each other and to the biosphere for survival.

Q5: Define global warming.
Ans:

• Increase in industries has led to increase in pollution.
• Carbon-dioxide is an important constituent of air.
• But increase in amount of CO₂ due to human activities has led to increase in global temperatures. This is termed as global warming.

Q6: Why is the surface of the earth a complex interface?
Ans: The surface of the earth is a complex interface, because three main components of the environment meet, overlap and interact on it.

• Lithosphere: The solid portion of the earth is Lithosphere. In Greek Litho means stone or rock. It means the sphere made of rocks is termed as Lithosphere.
• Atmosphere: The gaseous envelope surrounding the earth is Atmosphere. In Greek ‘atmo’ means air. The sphere made of air is atmosphere.
• Hydrosphere: The area containing water is called Hydrosphere. Word, Hydrosphere has been derived from the Greek word ‘Hydro’ which means water. Hydrosphere contains water in all its forms.

Biosphere has been derived from the Greek word ‘Bio’. It includes all parts of earth where all types of organisms live. It is the narrow zone of contact of land, water and air where all forms of life are found. All the four realms are not separate entities, they are considerably intermingled.

Q7: Explain the Composition of the Atmosphere.
Ans: Composition of the Atmosphere.

• Atmosphere is composed mainly of nitrogen and oxygen.
• They both make up about 99% of clean, dry air (Nitrogen 78%; Oxygen 21%)
• Other gases like Carbon-dioxide; argon and others comprise 1% by volume.
• Oxygen is the breath of life while nitrogen helps in the growth of living organisms.
• Carbon-dioxide is present in the air in minute amount but is very important.
• It absorbs heat radiated by the earth and keeps the surface of the earth warm.

Q8: What is air pressure? How is wind formed?
Ans:

• The atmosphere exerts pressure on the earth due to weight in the air. Thus air pressure is the weight of the air.
• Pressure varies from place to place.
• The difference in air pressure makes the air move.
• Moving air is known as wind. It means wind is formed due to the difference in air pressure.

Q9: What negative impacts on nature are caused by the felling of trees?
Ans: The felling of trees causes the following negative impacts on nature:

• Soil erosion is increased.
• Loose soil are deposited in river beds. Level of river beds rises and during excessive rains they are not capable of keeping the whole of water under control. Hence floods are caused.
• Felling of trees also reduces the quantity of oxygen we get from them. Hence new problems grow up.

Q10: Describe Lithosphere.
Ans: Lithosphere: The solid portion of the earth is termed as Lithosphere.

• It comprises (of) the rocks of earth’s crust.
• It also has shallow layers of soil that contain nutrient elements which are necessary for all types of organisms.

Q11: Which are the major domains on the earth?
Ans: The four major domains of the earth are lithosphere, atmosphere, hydrosphere and biosphere.

Q12: Which is the largest continent?
Ans: Asia is the world's largest continent. Asia accounts for one-third of the world's total land area.

Q13: What are the main gases that comprise atmosphere?
Ans: The main gases that comprise atmosphere are nitrogen, oxygen, carbon dioxide, argon etc.

Q14: Why is the Atlantic ocean world's busiest ocean in terms of commerce? 
Ans: The jagged and irregular coastline provides ideal conditions for harbours and ports, which makes the region suitable for transporting goods and transportation. As a result, the Atlantic Ocean is the most commercially active ocean in the world.

Q15: Mention reasons of fast removal of soil from slopes.
Ans: The reasons for rapid soil withdrawal from slopes are given below: . 

• Cutting plants to meet our needs. 
• Deforestation of land for agriculture.

Q16: Name the different layers of atmosphere.
Ans: The different layers of atmosphere are the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere.

Q17: What are the ocean basins?
Ans: The huge water bodies are called ocean basins.

Q18: What is the importance of atmosphere for us?
Ans: The atmosphere is important to us because it supplies air to breathe and protects us from the harmful effect of sunlight.

Q19: What is making water bodies unsuitable for use?
Ans: Contaminants in water bodies render them unusable. Dumping waste in lakes and rivers makes the water unclean to use and it is also detrimental to other lives.