The environment can be protected in a manner if we use the natural resources in limited way and do not harm or pollute any of the domains of the earth. There is a need to limit the use of resources of the earth to maintain the balance of nature between the domains of the lithosphere, the atmosphere and the hydrosphere.

The difference between isthmus and strait is as follows:
Isthmus It is a narrow strip of land that joins two landmasses. North America is linked with South America with a narrow strip of land called Isthmus of Panama.
Strait It is a narrow stretch of shallow water, which connects two large water bodies like seas and oceans. The Palk strait divides India and Sri Lanka.

The density of atmosphere varies with height is maximum at the sea level and decreasing while going up. The temperature also decreases when we go up.
The atmosphere exerts pressure on the earth The atmospheric pressure changes from place to place. Some places may have high pressure while some have low pressure.

The reasons behind fast removal of soil from slopes are given below:
(i) Cutting of plants for fulfilling our demands.
(ii) Clearing land for agriculture.

The indented and irregular coastline provides ideal condition for harbours and ports, which makes the region suitable for carriage of goods and transportation. Therefore, Atlantic ocean is the world's busiest ocean in terms of commerce.

The Equator passes on by the countries- Republic of Congo, Uganda and Kenya.
The tropic of cancer passes on through the countries-Morocco, Libya, Algeria and Egypt. The tropic of capricorn passes on through the country South Africa.

The earth is called 'blue planet' because of excess of watery surface on it which is around 71 per cent of earth's surface.

The different layers of atmosphere are the troposphere, the stratosphere, the mesosphere, the thermosphere and the exosphere.

Antarctica and Australia.

The four major domains of the earth are lithosphere, atmosphere, hydrosphere and biosphere.

(i) Lithosphere It is made-up of solid rock surface of the earth's crust and the thin layers of soil, which contain nutrient elements essential for life. There are two main divisions of the earth's surface. The large landmasses are known as the continents and massive water bodies are called ocean basins.
(ii) Hydrosphere The earth is called the blue planet. More than 71 per cent of the earth is covered with water and 29 per cent is with land. Hydrosphere consists of water in all its forms. As running water in oceans and rivers and in lakes, ice in glaciers, underground water and the water vapour in atmosphere, all comprise the hydrosphere.
(iii) Biosphere It is the zone with existing life. There are several organisms found here from microbes to large animals. All the organisms are linked with each other and biosphere as well. The living organisms in biosphere can be broadly divided into plant kingdom and animal kingdom.

(i) Indian ocean The Indian ocean is the only ocean named after a country, India. The shape of this ocean is almost triangular. It is bound by Asia in the North, in the West by Africa and in the East by Australia. (ii) Pacific ocean The Pacific ocean is the largest ocean. It is spread over one-third of the earth. The Pacific ocean is almost circular in shape. Asia, Australia, North America and South America surround it.
(iii) Arctic ocean It is connected with the Pacific ocean by a narrow stretch of shallow water called Berring strait.
The Arctic ocean is located within the Arctic Circle and surrounds the North Pole. It is bound by Northern coasts of North America and Eurasia.
(iv) Antarctic ocean The Southern ocean encircles the continent of Antarctica and extends northward to 60 degrees South latitude. Most of the time, it is covered with thick ice.