Textbook Solutions: The Four Realms of the Earth | Footprints Class 6: Book Solutions, Notes & Worksheets PDF Download

I. Tick (✔) the correct option.

1.
Ans: (c)
"It has the highest mountain on Earth— Mount Everest (8,848 m)."

2.
Ans: (b)
Continents make up 29 percent of the Earth's surface.

3.
Ans: (b)
"Africa is linked to Asia by the Isthmus of Suez."

4.
Ans: (a)
"Lake Superior, the largest freshwater lake in the world, is also located here."

5.
Ans: (b)
"Europe is bordered by the Mediterranean Sea to the south... the Strait of Gibraltar."

6.
Ans: (b)
"The smallest among all continents is Australia, located in the Southern Hemisphere. That is why it is often referred to as the continent Down Under."

7.
Ans: (c)
"A very interesting feature of this continent is the Great Barrier Reef."

8.
Ans: (b)
"The underwater mountain range on the floor of the Atlantic Ocean is called the Mid-Atlantic Ridge."

9.
Ans: (b)
"The gas which has the largest percentage in the Earth's atmosphere is nitrogen."

10.
Ans: (c)
"The mesosphere, which extends above the stratosphere..."

II. State whether the following statements are true or false. Rewrite the statements to correct them.

1.
Ans: False.
Sial comprises silicon and aluminum.

2.
Ans: True.

3.
Ans: False.
The physical environment includes land, water, and air.

4.
Ans: True.

5.
Ans: False.
Space stations are located in the thermosphere/ionosphere.

III. Answer the following questions In brief.

1.
Ans: The four realms are lithosphere, hydrosphere, atmosphere, and biosphere.

2.
Ans: The Great Barrier Reef is located in Australia.

3.
Ans: The biosphere is the zone of life on Earth, where living beings interact with the lithosphere, hydrosphere, and atmosphere.

4.
Ans: Habitat is the natural environment where life thrives and multiplies, providing a specific living space for organisms.

5.
Ans: Global warming is the rise in Earth's average atmospheric temperature. It is caused by the increased concentration of greenhouse gases, primarily carbon dioxide, in the atmosphere, trapping heat.

IV. Answer the following questions In detail.

1.
Ans: The lithosphere comprises the Earth's outermost layer, including the crust and the upper solid part of the mantle. It consists of continents (29%) and ocean beds (71%). A diagram can illustrate these components, depicting the Earth's structure like an onion, with labeled layers.

2.
Ans: The hydrosphere, including oceans, seas, lakes, rivers, and frozen water, is crucial for life. It provides habitats for diverse marine life, supports ecosystems, regulates temperature, and is vital for the hydrological cycle that ensures a continuous supply of fresh water.

3.
Ans: The hydrological cycle, also known as the water cycle, involves the continuous movement of water between the atmosphere, land, and oceans. It includes processes like evaporation, condensation, precipitation, and runoff, maintaining the balance of water on Earth.

4.
Ans: The atmosphere is the air surrounding Earth. It has different layers: troposphere (weather, 8-16 km), stratosphere (ozone layer, 50 km), mesosphere (meteors, 85 km), thermosphere/ionosphere (satellites, 640 km), and exosphere (outer space, 10,000 km). Each layer has distinct characteristics and importance.

5.
Ans: Ecological balance ensures harmony between living and non-living elements. It promotes biodiversity, stability, and sustainability. Human actions disrupting this balance, such as deforestation and pollution, have detrimental effects. Preserving ecological balance is crucial for Earth's resources and future generations.