Answer key

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Last edited 43 days ago by Learn LoopHQ.

Chapter: 03. Major Landforms Of The Earth

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How do geographical features of India, such as mountains, rivers, and coastal areas, influence its history and the lives of its people?

India’s diverse geographical features have profoundly shaped its history and influenced human life. The Himalayas in the north served as a formidable natural barrier, protecting the country from invaders, while mountain passes in the north-west facilitated trade and cultural exchanges with groups like the Central Asians. The vast network of rivers, such as the Ganga and Indus, nurtured fertile plains, providing ideal conditions for settled life and the flourishing of ancient civilizations. Additionally, India’s extensive coastline and surrounding seas enabled trade and interaction with seafaring nations. Even internal movements of people between north and south India were guided by the Vindhyas, Satpura mountains, numerous rivers, and the Deccan Plateau, collectively shaping the most momentous events in the nation’s past.

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Explain what plateaus are and classify them based on their formation, providing examples for each type.

Plateaus are uplifted sections of the Earth’s crust that are mostly flat or level on top but typically descend steeply to surrounding lowlands, often referred to as ‘tablelands’. Based on their formation, plateaus are classified into several types. Tectonic plateaus are formed by the movement of crustal plates, causing large portions of the Earth’s surface to rise, like the South African Plateau. Volcanic plateaus result from successive layers of lava solidifying over time, such as the Columbia Plateau. Dissected plateaus have irregular surfaces marked by canyons and gorges formed by erosion, like the Colorado Plateau. Intermontane plateaus, the most common type, are surrounded by mountains, with the Tibetan Plateau being a prime example. Lastly, piedmont plateaus lie between a mountain and a plain or ocean, an example being the Patagonia Plateau.

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Describe the formation and characteristics of fold mountains, including their two main types with examples.

Fold mountains are formed when layers of the Earth’s crust are compressed and folded by powerful forces generated by movements inside the Earth, often due to tectonic plate collisions. This compression causes the rock strata to buckle, forming peaks and valleys. There are two types: old fold mountains, formed over 250 million years ago, which have gentle slopes and low altitudes due to extensive weathering, like the Urals or the Aravallis. Young fold mountains, formed about 25 million years ago, are rugged and lofty, comprising the world’s highest ranges such as the Himalayas, Rockies, and Andes.

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Explain the two main processes responsible for the formation of Earth’s landforms.

Earth’s landforms are shaped by two primary processes: internal (endogenous) and external (exogenous). Internal processes originate inside the Earth, causing upliftment and sinking of the surface, which leads to the formation of features like folds and faults. External processes, on the other hand, constantly wear down and rebuild land surfaces through erosion, which is the wearing away of the surface, and deposition, which is the rebuilding of lowered surfaces. These external actions are carried out by agents such as running water, ice, wind, and even human activities.

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Discuss the importance of mountains in sustaining life and supporting human activities.

Mountains are vital for life as they act as natural storehouses of water, with many rivers originating from their glaciers, providing water for irrigation and hydroelectricity. Their diverse ecosystems support a rich variety of flora and fauna, contributing significantly to global biodiversity. Mountains also play a crucial role in regulating climate, causing rainfall and protecting regions from harsh winds. Furthermore, they offer essential mineral and metal deposits for industries, provide homes for millions of people, and offer forest products like fuel and food. Beyond necessities, mountains are popular tourist destinations, supporting recreational activities such as paragliding, river rafting, and skiing.

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Describe plains, their types, and their significance for human populations.

Plains, also known as lowlands, are vast, nearly flat areas of land typically less than 200 meters above sea level, primarily built by alluvium deposited by rivers. They are categorized into three types: Structural plains, formed by the uplift of seafloor sections; Erosional plains, resulting from the wearing away of mountains or plateaus by natural agents; and Depositional plains, created by large-scale sediment deposits from rivers, ice, or wind, including coastal plains. Plains are profoundly significant for humans as they are the most suitable landforms for habitation, supporting large populations and serving as the “granaries of the world” due to fertile agricultural land. Their flat terrain also greatly facilitates the construction of cities, industries, roads, and railways.

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