Class 9 Social Science (Contemporary India) Chapter 2 Physical Features of India

Key Concept: Location Identification

d) Andaman and Nicobar Islands

[Solution Description] Barren Island is part of the Andaman and Nicobar Islands, which are a group of islands in the Indian Ocean. It is known for being India’s only active volcano.

Key Concept: Human Settlement

c) Limits settlement growth due to scarcity of water.

[Solution Description] The Luni River, flowing through the Indian Desert, influences human settlements primarily due to its limited water availability. Since the region has low rainfall and the river does not reach the sea, water resources are scarce, limiting extensive agricultural activities and settlement expansion.

Key Concept: Mountain System Stability, Physiographic Divisions, Glaciers Characteristics

b) Unstable mountain system leading to dynamic glacier activity

[Solution Description] The Himalayan mountain system is geologically young and unstable, leading to dynamic interactions with the glaciers in the Great Himalayas. This instability promotes frequent glacial movements and advances, contributing to the formation of numerous valleys and unique topographical features. As a result, the active tectonic setting and climate variations heavily influence glacier dynamics, making them more sensitive and subject to rapid changes.

Key Concept: Delta Location

c) Eastern Coast

[Solution Description]

The Krishna River forms its delta along the eastern coast of India, which is influenced by geographical features such as the Eastern Ghats and the Bay of Bengal.

Key Concept: Highest Peak Identification

c) Anai Mudi

[Solution Description] Anai Mudi is recognized as the highest peak in the Western Ghats with an elevation of 2,695 metres. This peak is located within the Indian state of Kerala.

Key Concept: River Influence

c) Godavari

[Solution Description] Among the major rivers listed in the syllabus, the Mahanadi, Godavari, Krishna, and Kaveri are known for forming significant deltas on the eastern coast. These contribute to the fertility of the coastal plains. The Godavari, being one of the largest, plays a substantial role in delta formation and influencing the fertility.

Key Concept: Riverine Islands

c) Assertion is true, but Reason is false.

[Solution Description]

The assertion states that riverine islands are commonly found in the lower courses of the Ganga and Brahmaputra rivers. This is true because as these rivers approach the sea, they slow down, allowing for sediment deposits that form islands.

The reason provided claims that these rivers have a greater velocity in their lower courses due to steeper slopes. This is incorrect; actually, the slope becomes gentler resulting in decreased velocity. Thus, while the assertion is true, the reason is false.

Therefore, the correct answer is (c).

Key Concept: Formation Material

c) Alluvial deposits

[Solution Description] As per the syllabus, the Northern Plains are primarily formed from alluvial deposits.

Key Concept: Simple Identification

b) Re-emerging rivers

[Solution Description] One of the key characteristics of the Terai region is the presence of re-emerging rivers, which contribute to its swampy conditions and support rich biodiversity.

Key Concept: Geographic Influence

b) River dissection

[Solution Description] The Eastern Ghats are described as discontinuous and irregular due to being dissected by rivers draining into the Bay of Bengal. These river dissections contribute significantly to their discontinuity.

Key Concept: Hydrological Cycle, Human Impact

d) It disrupts the natural flow, leading to reduced downstream water availability and altering groundwater recharge patterns.

[Solution Description] The Luni River plays a crucial role in the local hydrological cycle by providing one of the few sources of surface water in the Indian Desert. Human activities, such as dam construction and water diversion for agriculture, significantly alter the natural flow of the river. These interventions can lead to reduced downstream water availability, disrupting the balance of groundwater recharge and evaporation processes critical for sustaining limited vegetation and mitigating desert conditions.

Key Concept: Climate Impact Analysis, Rainfall Pattern Implications

c) Limits human habitation due to scarce water resources

[Solution Description] The Indian Desert has an arid climate with very low annual rainfall, typically below 150 mm per year. This condition severely limits water availability, impacting agriculture, drinking water supply, and overall human settlement. Low rainfall leads to limited vegetation cover, affecting agricultural productivity and necessitating unique adaptations for survival.

Key Concept: River Drainage

c) Damodar

[Solution Description]

The Chotanagpur plateau represents a further eastward extension of the Central Highlands. It is primarily drained by the Damodar river, which has significant importance for its mineral-rich terrain and industrial relevance.

Key Concept: Comparative Geography, Geographical Analysis

c) Serves as a reference point for regional topographic variation.

[Solution Description] Mahendragiri, with an elevation of 1,501 meters, is a prominent feature within the Eastern Ghats but does not divide them into distinct sections. Instead, it acts as one of the notable elevations contributing to the varied topography of the region. Unlike the Western Ghats that serve as significant watersheds, Mahendragiri’s role is more about marking a point of high elevation within an otherwise irregular and discontinuous range.

Key Concept: Definition Recall

b) New alluvium, highly fertile, renewed annually

[Solution Description] Khadar is defined as the newer deposits found in floodplains that are highly fertile and renewed annually.

Key Concept: Punjab Plains

c) Indus

[Solution Description]

The Punjab Plains are primarily formed by the Indus river system. It includes several major tributaries like Jhelum, Chenab, Ravi, Beas, and Sutlej which collectively contribute to the fertility of this region.

Key Concept: True Characteristics

b) Fertile soil

[Solution Description] The Northern Plains are ideal for intensive agriculture due to their fertile soil, which results from the deposition of alluvium by Himalayan rivers.

Key Concept: River Systems

d) Godavari

[Solution Description] The river systems forming the Northern Plains include Indus, Ganga, and Brahmaputra. Godavari is not part of these systems.

Key Concept: Rainfall Influence

d) By causing orographic rain through moist winds

[Solution Description]

The Western Ghats cause orographic rain by facing moist winds coming from the southwest monsoon, resulting in heavy rainfall on their windward side.

Key Concept: Detailed Comparison

c) The Great Himalayas have higher peaks and more glaciated terrain than the Lesser Himalayas.

[Solution Description] The Great Himalayas, or Himadri, are higher in elevation compared to the Lesser Himalayas or Himachal. The Himadri range features some of the world’s highest peaks, like Mount Everest, while the Himachal has moderate altitudes and is known for its hill stations.

Key Concept: Basic Identification

c) Barren Island

[Solution Description] India’s only active volcano is located on Barren Island, part of the Andaman and Nicobar Islands group.

Key Concept: Administrative Role

c) It is the administrative headquarters.

[Solution Description] Kavaratti serves as the administrative headquarters for the Lakshadweep Islands, meaning it is the center of government and administration.

Key Concept: Plateau Features

b) Igneous and Metamorphic rocks

[Solution Description] The Peninsular Plateau is primarily composed of old crystalline, igneous, and metamorphic rocks, as mentioned in the syllabus.

Key Concept: Regional Divisions

d) Bhabar

[Solution Description] Bhabar is the soil type that consists of coarse particles such as pebbles and gravels. It is found at the foothills of the Himalayas where streams descending from the mountains deposit their load due to sudden reduction in velocity. These soils are porous and hence do not retain water.

Key Concept: Geological History

c) The Peninsular Plateau

[Solution Description] The Peninsular Plateau, an ancient landmass, is composed of igneous and metamorphic rocks, making it one of the most stable parts of India’s physiography.

Key Concept: River Dissection

d) Mahanadi

[Solution Description]

The Eastern Ghats are dissected by several rivers that drain eastward into the Bay of Bengal. Among these rivers, the Mahanadi is one of the major rivers that cut through the Eastern Ghats before emptying into the bay.

Key Concept: Climbing Challenges, Cultural Significance

b) Kanchenjunga

[Solution Description] Kangchenjunga is renowned for its formidable climbing routes characterized by steep faces, avalanches, and unpredictable weather, making it one of the toughest climbs. Additionally, Kangchenjunga holds cultural and religious significance for communities residing in Sikkim, India and eastern Nepal. Due to these beliefs, access to the summit was historically restricted, and even today, many climbers stop slightly short as a mark of respect.

Key Concept: Hill Ranges

c) Aravali Hills

[Solution Description] The Aravali Hills are located on the western side of India and form the eastern boundary of the Indian Desert, which is also known as the Thar Desert. This mountain range runs approximately from northeast to southwest across Rajasthan.

Key Concept: Coastal Plain Characteristics

b) Narrow and sandwiched

[Solution Description] The Western Coastal Plains are known for being narrow and sandwiched between the Western Ghats and the Arabian Sea, making them distinct in terms of geography compared to other regions.

Key Concept: Coastal Sections

b) Kannad Plain

[Solution Description] The western coast of India consists of three sections: Konkan, Kannad Plain, and Malabar Coast. The Kannad Plain is its own distinct central section.

Key Concept: Comparative Analysis, Human Interaction

d) Kotli Dun has greater displacement due to extensive farming.

[Solution Description] In both Kotli Dun and Patli Dun valleys, human activities like agriculture contribute to sediment displacement. However, if we analyze the agricultural practices and their extent, Kotli Dun may experience higher sediment displacement due to more extensive farming compared to Patli Dun. This results from varying soil management techniques and the intensity of cultivation. These factors can lead to different levels of erosion and sedimentation in each region.

Key Concept: Relief Features

c) Khadar

[Solution Description] Along the banks of the rivers in the Northern Plains, there are fertile floodplains known as ‘Khadar’. This area is regularly renewed by floods, making it very suitable for agriculture.

Key Concept: Eastern Hills

d) Mizo Hills

[Solution Description] The Purvachal or the Eastern hills include several hill ranges. As per the provided syllabus, the Mizo Hills form a part of the Purvachal.

Key Concept: Geological Composition, Altitudinal Variations

b) Frequent landslides due to unstable geological formations

[Solution Description] The altitude of 3,700 to 4,500 meters combined with highly compressed and altered rocks suggests that landslides could be a significant challenge. These geological conditions are conducive to instability, especially during events such as heavy rainfall or earthquakes.

Key Concept: Geological Composition, Valley Formation

c) Tectonic uplift and folding of rock layers

[Solution Description]

The Kashmir Valley’s formation can be attributed mainly to tectonic uplift and folding processes rather than glacial erosion or river deposition. This region has been shaped over millions of years as a result of the Indian plate colliding with the Eurasian plate, leading to the compression and alteration of rocks. The compressive forces caused the valley’s uplift and its current structure.

Key Concept: Mountain Range Dynamics, Geographical Influence

c) Tectonic activity leading to fold mountains

[Solution Description] The Himalayan mountain system, including the Kumaon Himalayas, is geologically young and structurally composed of fold mountains. This folding activity due to tectonic forces is responsible for creating high peaks in the region.

Key Concept: Regional Division Analysis, Geological Composition

d) The Great Himalayas

[Solution Description]

The Great Himalayas are characterized by their unique geological composition. They consist of highly compressed and altered rocks along with a granite core. Moreover, the folds in this region are asymmetrical, which is a noteworthy feature specific to the Great Himalayas.

Key Concept: Peak Characteristics

d) Doda Betta is the second highest peak in the Western Ghats.

[Solution Description]

Doda Betta, at 2,637 meters, is the second highest peak in the Peninsular Plateau and is located in the Western Ghats. Anai Mudi is the highest with a height of 2,695 meters. Thus, Doda Betta cannot be the highest.

Key Concept: Geological History, Fault Impact

c) It affects mineral distribution

[Solution Description] The fault separating the Peninsular Plateau from the Chotanagpur Plateau plays a vital role in influencing the geological features of the Meghalaya region. This fault line results in variances in mineral distribution due to tectonic activity and altered rock formations over time. To assess the impact, we analyze the composition and resource availability. As minerals tend to accumulate along fault lines, it significantly affects mineral distribution in the region.

Key Concept: Island Identification

b) Lakshadweep

[Solution Description]

The Lakshadweep islands are situated in the Arabian Sea and are the closest to the Malabar Coast of Kerala. These islands are known for their unique marine biodiversity and coral reefs.

Key Concept: Geological Stability

c) Due to its ancient crystalline rock composition

[Solution Description] The Peninsular Plateau is seen as one of the most geologically stable regions due to its composition of ancient crystalline igneous and metamorphic rocks that date back billions of years. These rocks are less susceptible to tectonic activity, making the area relatively stable over geological timescales compared to other parts of the world with more recent formations.

Key Concept: Island Identification

b) Lakshadweep

[Solution Description]

Lakshadweep Islands are known for being a group of small coral islands situated off the southwestern coast of India. This archipelago covers an area of 32 square kilometers and is notable for its coral origin.

Key Concept: River Dissection

c) Godavari

[Solution Description] The river dissects the Eastern Ghats, which are irregular and discontinuous mountain ranges on the eastern side of India. These rivers flow towards the east and drain into the Bay of Bengal. Among the options provided, the Godavari River is one of the major rivers that dissect these mountains.

Key Concept: Peak Significance, Pass Functionality

d) Passes enable trade routes, and peaks support biodiversity and tourism.

[Solution Description] Passes like Thal Ghat facilitate transportation and trade between different regions, playing a crucial role in regional economies. Peaks like Anai Mudi are significant for biodiversity, providing habitats for various species, and they attract tourists interested in trekking and nature exploration. Thus, both geographical features contribute to ecological conservation and economic development.

Key Concept: Historical Name Change

b) 1973

[Solution Description] The renaming of the islands to Lakshadweep occurred in the year 1973. This was an official change from their previous names: Laccadive, Minicoy, and Amindive.

Key Concept: Geographical Challenges, River Dynamics

b) It leads to frequent flooding, disrupting farming cycles.

[Solution Description] Distributaries form when a river overflows its banks, causing water to spread across a wide area. This can lead to waterlogging, affecting soil quality and hindering traditional crop cultivation methods in those regions. Farmers may need to adapt by choosing water-resistant crops or implementing irrigation techniques suited to variable water distribution.

Key Concept: River Dissection, Orographic Rain

b) By channeling moist air directly over Western Ghats

[Solution Description]

Rivers disjoining the Eastern Ghats flow eastward towards the Bay of Bengal. In contrast, moist air currents from the Arabian Sea push against the Western Ghats causing orographic rainfall due to elevation rise. This moisture-laden wind pattern ensures heavy precipitation on the western slopes of these ghats, influencing the monsoon climate. While rivers mainly dissect the Eastern Ghats, they enable moisture transport that indirectly assists in creating conditions for such rain.

Key Concept: Synthesis, Real-World Application

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

[Solution Description] The assertion highlights the importance of conserving biodiversity in the Himalayas with respect to its role in global climate change mitigation. The reason correctly describes how the dense forest cover in the Himalayas absorbs large amounts of carbon dioxide, acting as a significant carbon sink. Both statements are true and interrelated, where the function mentioned in the reason supports the assertion’s emphasis on conservation efforts for climate regulation.

Key Concept: Geographical Significance

c) Chilika Lake is the largest saltwater lake in India.

[Solution Description] Chilika Lake is known as India’s largest saltwater lake, and it is located in the state of Odisha.

Key Concept: Physiographic Impact, Geological Stability

b) Their instability leads to scattered settlements with adaptive structures.

[Solution Description] The Assam Himalayas, bordered by significant river systems like the Teesta and Dihang, are characterized by young mountainous terrain with frequent tectonic activities. This makes the region geologically unstable, influencing habitation patterns due to landslide susceptibilities and seismic activities. Settlements often need to adapt to these conditions, either through geography-based planning or structural reinforcements. Analyzing these factors helps understand settlement dispersion across the Assam Himalayan region.

Key Concept: Geological Stability, Altitudinal Variation

b) Asymmetrical folding due to tectonic activity

[Solution Description] The geological instability of the Great Himalayas is primarily due to the asymmetrical folds in the mountain range. These folds are created by tectonic plate movements which lead to stresses and deformations within the rock structures. Additionally, the presence of numerous glaciers adds dynamic forces that can further destabilize the region.

Key Concept: Elevation Comparison

c) Western Ghats are higher than Eastern Ghats

[Solution Description] According to the syllabus, the Western Ghats have a higher elevation ranging from 900 to 1600 metres compared to the Eastern Ghats.

Key Concept: Coastal Geography

c) Northern Circar

[Solution Description] The eastern coastal plains are divided into two main sections: the Northern Circar and the Coromandel Coast. These names represent subdivisions within the larger expanse of the eastern coast.

Key Concept: Plateau Slope

a) West to East

[Solution Description]

As stated in the syllabus, the Deccan Plateau is higher in the west and slopes gently eastwards.

Key Concept: Altitudinal Variation Impact, Real World Application

c) They require adaptive strategies like crop rotation and transhumance.

[Solution Description]

Altitudinal variations result in distinct microclimates across different elevations in the Great Himalayas. Higher altitudes experience colder temperatures and shorter growing seasons, limiting crop types that can be cultivated. Lower altitudes benefit from milder climates suitable for diverse agriculture. These variations cause farmers to practice transhumance, moving livestock between fixed summer and winter pastures, and cultivating altitude-suitable crops like barley at higher levels while rice grows at lower ones.

Key Concept: Active Volcano

b) Andaman Islands

[Solution Description] India’s only active volcano is located on Barren Island which is a part of the Andaman and Nicobar Islands.

Key Concept: Regional Demarcation, Altitudinal Variation

c) Different altitudes support varied climates and biodiversity.

[Solution Description] The Himachal or lesser Himalaya has an altitude range of 3,700 to 4,500 meters. This variation in altitude affects both climate and ecology. As elevation increases, the temperature generally decreases, leading to a cooler climate at higher altitudes. This also results in distinct vegetation zones. Higher elevations may support alpine or sub-alpine ecosystems, while lower regions can have more diverse temperate forests. Thus, the altitude range influences both the climate and the type of vegetation that can thrive, making it ecologically significant.

Key Concept: Environmental Impact

b) Provide shelter for animals

[Solution Description] Sand dunes impact local habitats by providing unique microenvironments. They can affect factors such as temperature and humidity, and offer shelter to certain species, thereby affecting the overall ecosystem.

Key Concept: River Contribution

d) Narmada

[Solution Description] The Coromandel Coast sees delta formations by major rivers like Mahanadi, Godavari, Krishna, and Kaveri. The Narmada river flows westward into the Arabian Sea and therefore doesn’t contribute to delta formation on this coast.

Key Concept: Coral Reef Types, Volcanic Activity

c) Barren Island in Andaman & Nicobar hosts an active volcano unlike Lakshadweep.

[Solution Description] The Lakshadweep islands are known for their coral reef systems since they consist mainly of small coral islands, which play a critical role in marine biodiversity. On the other hand, the Andaman & Nicobar islands have India’s only active volcano located on Barren Island, contributing to unique geological formations.

Key Concept: Location Knowledge

d) Arabian Sea

[Solution Description]

The Malabar Coast runs along the Arabian Sea. It stretches down the western coast of India, providing access to maritime routes and influencing the coastal climate.

Key Concept: Geological Composition, Structural Analysis

c) Granite in the Great Himalayas contributes to greater structural stability.

[Solution Description] The Great Himalayas are primarily composed of granite, which is known for its hardness and durability. This makes the structure more stable and less prone to erosion compared to the Lesser Himalayas, which consist of highly compressed and altered rocks that are more susceptible to weathering and deformation.

Key Concept: Sedimentary Composition

c) Sedimentary

[Solution Description] The Purvachal hills, located in northeastern India, are primarily composed of sedimentary rocks. This characteristic distinguishes them from other regions dominated by metamorphic or igneous formations.

Key Concept: Island Identification

a) Andaman and Nicobar

[Solution Description] The Andaman and Nicobar Islands are divided into two categories based on their geographical position: the Andaman Islands are located to the north, while the Nicobar Islands are situated to the south.

Key Concept: Environmental Impact, Climate Variation

c) Increased human activity altering rainfall

[Solution Description] The influx of tourists in the Kullu Valley leads to deforestation and increased pollution, particularly from vehicles and waste left by visitors. These activities contribute to changes in local microclimates, such as altered rainfall patterns and temperature fluctuations. The increase in pollution-related activities exacerbates these climatic variations.

Key Concept: Geological Features

a) Alluvial deposits

[Solution Description] The Shiwaliks, known for extending over a width of 10-50 Km with altitudes between 900 and 1100 metres, are composed mainly of unconsolidated sediments brought down by rivers from the higher ranges.

Key Concept: Geological Composition, River Influence

b) It marks the eastern boundary, allowing for unique sedimentary classification

[Solution Description] The Brahmaputra river acts as a geological marker for the eastern boundary of the Himalayas. This demarcation allows geologists to classify the Purvachal region distinctly within the Himalayan mountain range. Its position helps in distinguishing regional sedimentary compositions like strong sandstones found here.

Key Concept: Seasonal Streams

c) Rainy season

[Solution Description] In the Indian Desert, streams generally appear during the rainy season. Despite the overall low annual rainfall, the sudden rainfall can cause streams to form temporarily before they disappear into the sand.

Key Concept: Plateau Divisions

b) Central Highlands and Deccan Plateau

[Solution Description] The Peninsular Plateau consists of the Central Highlands and the Deccan Plateau as its two main divisions.

Key Concept: Advanced Formation Analysis, Environmental Impact

d) Tectonic uplift

[Solution Description] The factors contributing to environmental degradation in Duns mainly include activities like deforestation and urbanization, which disturb the natural habitat and ecosystem. Tectonic activity affects geological formation but does not directly cause degradation in a human-induced context.

Key Concept: Rainfall Mechanism, Real-world Application

c) Higher altitudes lead to increased rain on the windward side and lesser on the leeward side.

[Solution Description] The Western Ghats have an average elevation of 900–1600 meters and cause orographic rainfall. As moist winds from the Arabian Sea meet the Western Ghats, they are forced to rise, cool, and condense, causing heavy rainfall on the windward side. On the leeward side, the air descends, warms up, and becomes dry, resulting in less rainfall.

Key Concept: Coastal Plain Sections

b) Kannad

[Solution Description] The section of the western coastal plain located between Goa and Mangalore is known as the Kannad Plain. The Western Coastal Plains comprise three sections: the Konkan coast (Mumbai to Goa), the Kannad Plain (Goa to Mangalore), and the Malabar Coast (south of Mangalore).

Key Concept: Basic Definition

c) Old alluvium

[Solution Description]

Bhangar is classified as old alluvium due to its formation from older sediment deposits in the northern plains.

Key Concept: Geographical Features

d) Majuli

[Solution Description] Majuli is the largest inhabited riverine island in the world, situated on the Brahmaputra River.

Key Concept: Peak Identification

b) Anai Mudi

[Solution Description] Anai Mudi is the highest peak located in the Western Ghats. Standing taller than other notable peaks such as Doda Betta and Mahendragiri, it plays a key role in influencing local climate and biodiversity.

Key Concept: Basic Definition

b) Pebble-covered region

[Solution Description] The Bhabar region is a pebble-covered area formed by the deposition of pebbles and gravel brought down by streams and rivers from the mountains.

Key Concept: Width and Ecology, Width and Climate Change

a) Restricts upward migration paths resulting in population isolation

[Solution Description] The significant altitudinal and width differences across the Himalayas create diverse ecological niches. In regions like Arunachal Pradesh, where the Himalayas are narrower, species have fewer options to migrate upwards during warming events, leading to potential habitat loss. Conversely, in wider regions such as Kashmir, there are more varied altitudinal ranges facilitating easier species migrations to suitable climates.

Key Concept: River Systems

d) Luni

[Solution Description] The Luni River is the primary river flowing through the arid desert region in India, providing vital water resources to this otherwise dry area.

Key Concept: Location-based

d) Maharashtra and Goa

[Solution Description] The Konkan Coast primarily stretches between Mumbai in Maharashtra and Goa.

Key Concept: Altitudinal Impact, Structural Formation

b) Increased altitude enhances weathering and erosion, leading to diverse geological formations.

[Solution Description] To solve this, one must consider how altitudinal differences affect pressure, temperature, and erosion rates, which are key factors in geological formations. Higher altitudes generally face greater pressures and temperature variations, leading to increased erosion and weathering processes. This can cause more pronounced folding and faulting, affecting structural integrity. Therefore, regions with significant altitudinal variation may exhibit diverse geological features due to differential stress impacts.

Key Concept: Coastal Features

d) Godavari

[Solution Description]

The Northern Circar region includes deltas formed by major rivers such as the Mahanadi, Godavari, and Krishna.

Key Concept: Range Comparison

a) Pir Panjal

[Solution Description] Among the ranges mentioned in the syllabus, the Pir Panjal range is noted as the longest and most important range within the lesser Himalayas.

Key Concept: Ghats Characteristics

b) They cause orographic rainfall

[Solution Description] The Western Ghats are continuous and have an elevation between 900-1600 metres, causing orographic rain due to their height and continuity.

Key Concept: Geological Significance, Plateau’s Economic Role

d) The fertile soil supports large-scale cotton farming.

[Solution Description] The Deccan Trap is known for its black soil, which is a result of its volcanic origin. This region is economically significant due to the fertility of its black soil, which supports extensive cotton cultivation. Additionally, the volcanic rocks contribute minerals beneficial for agriculture.

Key Concept: Structural Analysis, Comparative Geography

c) Andes; characterized by sharp peaks and deep valleys due to active folding.

[Solution Description] The Himalayas are formed through the collision between the Indo-Australian and Eurasian tectonic plates, resulting in folding. Similarly, the Andes mountains were formed by the subduction of oceanic plates beneath continental plates, also resulting in fold mountains. This process creates jagged peaks, deep valleys, and high altitudinal gradients in both ranges.

Key Concept: Strategic Importance

b) Their location near the Malacca Strait

[Solution Description] The strategic importance of the Andaman and Nicobar Islands is majorly due to their location in the Bay of Bengal, which acts as a watch point for monitoring sea routes and maritime activities. They are situated near the Malacca Strait, one of the busiest maritime trade routes in the world, providing India with a strategic advantage.

Key Concept: River in Desert

c) Luni

[Solution Description] The Luni River is the only significant river that flows through the Indian Desert. Other rivers like Ganga, Yamuna, and Narmada do not flow through this region.

Key Concept: Volcanic Origin, Complex Topography

c) The Western Ghats cause orographic rainfall on their western side, leading to a rain shadow on the eastern side.

[Solution Description] The Western Ghats are higher than the Eastern Ghats on the Deccan Plateau. Due to their altitude and position, they block moist winds coming from the southwest during the monsoon, causing heavy rainfall on their western slopes while creating a rain shadow region on the eastern side. This phenomenon is known as orographic rain.

Key Concept: Rainfall and Geographical Changes, Rainfall Patterns

b) It creates and reshapes sand dunes

[Solution Description]

The Indian Desert’s climate is arid with annual rainfall less than 150 mm. This leads to limited vegetation cover and high evaporation rates. Over time, the rainwater that does fall forms ephemeral streams, which quickly dry up due to the sandy terrain and lack of consistent flow. This process results in significant erosion and contributes to the formation of sand dunes as particles are carried by wind and deposited in different areas. Therefore, the primary geographical change seen due to low and inconsistent rainfall is the creation and reshaping of sand dunes.

Key Concept: Regional Names Analysis, River Demarcation

d) Teesta and Dihang

[Solution Description]

The Assam Himalayas are located towards the eastern part of the Himalayas. According to the syllabus, the Brahmaputra marks the eastern-most boundary of the Himalayas. Thus, the region where the Assam Himalayas lie should be between rivers that lead up to the Brahmaputra. By process of elimination and knowledge of regional geography, we find that the Teesta and Dihang rivers provide the accurate demarcation for the Assam Himalayas.

Key Concept: Geological Stability

d) It lacks major tectonic activity

[Solution Description] The stability of the Peninsular Plateau compared to regions such as the Himalayas can be attributed to its ancient landmass composition and lack of tectonic activity. These factors make it less prone to earthquakes and geological disturbances, unlike the younger, actively rising Himalayas.

Key Concept: Soil Properties

c) High clay content

[Solution Description]

Black soil, also known as regur soil, has a fine clayey texture which allows it to retain moisture efficiently. This high clay content contributes significantly to its capacity to hold water, making it suitable for crops like cotton that require significant moisture.

Key Concept: Riverine Influence, Purvachal Hills

b) Through extensive erosion leading to unique valley formations

[Solution Description] The Brahmaputra River plays a pivotal role in defining the topographical features of the Purvachal hills by facilitating erosion and sediment deposition. It creates fertile floodplains conducive to diverse flora and fauna. Additionally, the river’s meandering path and seasonal floods enhance biodiversity and create varied habitats along its course.

Key Concept: Geological Formation, Comparative Analysis

c) They are primarily made up of sedimentary sandstones.

[Solution Description] The Eastern Hills are mainly composed of strong sandstones, classifying them as sedimentary rocks. In contrast, the main Himalayas have varied rock compositions, including metamorphic and igneous types. This differentiation in rock type impacts their formation processes and visual appearances.