Additional Question:
Que: Which is larger - Europe or Australia?
Ans: Europe is larger than Australia.
Que: How is nitrogen a significant gas?
Ans: Nitrogen helps in the growth of living organisms.
Que: What is the Junction of carbon dioxide?
Ans: Carbon dioxide absords the heat rediated by the earth and thus keeps the planet warm.
Que: What is the height of the mt. Everest.
Ans: The height of the mt. Everest is 8,848 meters.
Que: In which Hemisphere does asoia life?
Ans: Asia lies in the Eastern Hemisphere.
Que: Name the world's largest hot desert. Where is the locted.
Ans: The sahara desert. It is located in Africa.
Que: How is North America linked to south America?
Ans: North America is linked to south America by a narrow strip of land called the Isthmus of panama.
Que: Name of Oceans that surround the continent - North America.
Ans: The Pacific Ocean, the Atlantic ocean and the Artic Ocean.
Que: Which two oceans surround South America on the east and the west.
Ans: On the east - the Atlantic ocean On the west - the pacific Ocean.
Que: Name the research stations of India in Antaractica.
Ans: Maitri and Dakshin Gangotri.
Que: What percent of the earth is covered with water?
Ans: More than 71 percent of the earth is covered with water.
Que: What percent of earth is covered with land.
Ans: 29 percent of earth is covrered with land.
Que: How much of the earth's water is found in the oceans?
Ans: More than 97 percent of the earth's water is found in the ocean.
Que: Why is the ocean water not fit for human use?
Ans: It is becuse the ocean water is very salty.
Que: Why do the mountaineers carry with the oxygen cylinders?
Ans: The mountaineers carry with them oxygen cylinders so that they can easily breathe at high altitudes.
Que: What is the nature of the temperature?
Ans: The temperature decreases as we go upwards.
Que: Name the continents that surround the pacific oceans.
Ans: Asia, Australia, North America and South America.
Que: Which is the busiet oceans from the point of view of commerce?
Ans: The Atlantic ocean is the busiest ocean from the point of view of commerce.
Que: mention two reasons of fast removal of soil from stops.
Ans: (i) Cutting of forests for wood.
(ii) Clearing land for agriculture.
Que: What happened to Andman and Nicobar island durig Tsunami?
Ans: Parts of these island were submerged under water during Tsunami.
Que: What makes the mater of lakes and rivers unsuitable for human use.
Ans: Discharge of waste material into lakes and rivers makes the water unsuitable for human use.
Que: Mention any two reasons of air pollution.
Ans: (i) Emission from industries.
(ii) Emission from vehicles.
Que: Mention the three main components of the environment.
Ans: the three main components of the environment are - the lithosphere, the atmosphere and the hydrosphere. The lithosphere is the solid portion of the earth. The gaseous layers that surround the earth is the atmosphere. The atmosphere is made up of oxygen, nitrogen, carbondioxide and other gases. The hydroshere refers to the big area of the water that cover the earth's surface. This water is in the fors of ice, water and water vapour.
Que: Write a short note on the 'hydrosphere'.
Ans: The hydrosphere refers to the water bodies that are found on the earth's surface. More than 71% of the earth is covered with water. This water is found in all its forms - ice, water and water vapour. Running water in oceans and rivers and in lakes, ice in glaciers, underground water and the water vapour in atmosphere. More thanj 97% of the earth's water is found in oceans. the ocean water is very salty, herce not to human utility. A large proportion of the rest of water is in the from of the icesheets and glaciers of under the ground. A very small percentage (0.03%) is available as frash water. It is this water that we use.
Que: Explain biophere - the domain of life.
Ans: The biosphere is a narrow zone of the earth where land, water and air interact with each other to support life. it is in the this zone that life exists. There are several species of organisms that very in size from microbers and bacteria to large mammals. All living organisms including human are linked to each other and to the biophere for survival.
Que: Give an account of the composition of the atmosphere. Also, discuss the importance of the components.
Ans: The atmosphere is composed mainly of nitrogen and oxygen. Together they make up about 90% of clean, dry air. Nitrogen 78% and oxygen 21%. A part from these two major gases, there are other gases too in the atmosphere. These gases include carbon dioxide, argon and other comprise 1% by volums.
Oxygen is the breath of life while nitrogen helps in the growth of living organisms. Carbon dioxide absords heat radiated by the earth. In this way, it keeps the planet warm. It is also essential for the growth of plants.
Que: What is atmosphere? Write about its different layers.
Ans: The atmosphere is a thin blanket of air that surrounds the earth. It provides us with the air we breathe and protects us from the harmful effects of sun's rays. the atmosphere extends up to a height of about 1,600km. The atmosphere is divided into five layers based on composition, temperature and other properties. These layers are - the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere.
