Major Domains of the Earth

Q18. What happened to Andaman & Nicobar Islands during Tsunami?

Ans. Parts of Andaman & Nicobar islands were submerged under water during Tsunami.

Q19. How is elevation of land measured?

Ans. Elevation of land is measured from the level of the sea, which is taken as zero.

Q20. Write the major divisions of the earth’s surface.

Ans. The major divisions of the earth’s surface are continents and ocean basins.

Q21. Which is considered as busiest ocean from the point of view of commerce?

Ans. The Atlantic Ocean is considered as busiest ocean from the point of view of commerce.

Q22. What makes water of lakes and rivers unsuitable for human use?

Ans. Discharge of waste material into lakes and rivers makes the water unsuitable for human use.

Q23. What links North America to South America?

Ans. North America is linked to South America by a very narrow strip of land called the Isthmus of Panama.

Q24. What is ‘Global Warning’?

Ans. Increase in the amount of CO₂ leads to increase in global temperatures.

This is termed as global warming.

Q25. What are the major components of the Lithosphere?

Ans. It comprises the rocks of the earth’s crust and the thin layers of soil that contain nutrient elements which sustain organisms.

Q26. Why the earth is called a blue planet?

Ans. The earth is called the blue planet because more than 71 percent of the earth is covered with water and 29 percent is with land.

Q27. What are the chief movements of the ocean water?

Ans. The chief movements of ocean waters are the waves, the tides and the ocean currents.

Q28. Name the five major oceans of the world.

Ans. The five major oceans are the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Southern Ocean and the Arctic Ocean, in order of their size.

Q29. Why do the climbers experience problems in breathing at high altitudes?

Ans. The climbers experience problems in breathing due to decrease in the density of air at high altitudes.

Q31. What are the components of the Hydrosphere?

Ans. Running water in oceans and rivers and in lakes, ice in glaciers, underground water and the water vapor in atmosphere, all comprise the hydrosphere.

Q32. What causes fast removal of soil from slopes?

Ans. Cutting of forests for fulfilling our needs of wood, or clearing land for agriculture causes fast removal of soil from slopes.

Q33. Write a short note on the continent - Australia.

Ans. Australia is the smallest continent that lies entirely in the Southern Hemisphere. It is surrounded on all sides by the oceans and seas. It is called an island continent.

Q34. Name the different layers of the atmosphere.

Ans. The atmosphere is divided into five layers: troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere.

Q35. Which two continents lie entirely in the Southern and Northern Hemisphere?

Ans. Two continents lying entirely in northern hemisphere are North America and Europe. Two continents lying entirely in southern hemisphere are South America and Australia.