Q. The vegetation of savannah consists of grassland with scattered small trees. The forest development in such areas is generally kept in check by one or more or a combination of some conditions.

Which of the following are such conditions?
1. Burrowing animals and termites.
2. Fire
3. Grazing herbivores
4. Seasonal rainfall
5. Soil properties

Select the correct answer using the code given below.

(a) 1 and2
(b) 4 and 5
(c) 2, 3 and 4
(d) 1, 3 and 5

Answer: (c) 2, 3 and 4

  • Tropical Wet and Dry Climate or Sudan Climate.
  • This type of climate has alternate wet and dry seasons similar to monsoon climate but has considerably less annual rainfall.
  • Also, there is no distinct rainy season like in the monsoon climate.
  • There are Only two seasons – winter and summer. Rains occur in summer.
  • Floods and droughts are common.
  • The savanna landscape is typified by tall grass and short trees.
  • Here is depends on grazing intensity and not the burrowing animals or termites.
  • Bush fires are common in Savannah because of the alternate wet and dry seasons which can modify the forest.
  • Grazing intensity is a major reason for the type of Savannah, so Grazing herbivores do contribute to keeping a check on forests.
  • It has seasonal rainfall based on which it is divided into wet, dry or thornbush.
  • Soil properties influence the type of Savannah and its vegetation but don’t contribute to checking it once formed.
  • Tropical savanna climates are most commonly found in Africa, Asia, and South America. The climate is also prevalent in sections of Central America, northern Australia, the Pacific Islands, in sections of North America, and some islands in the Caribbean. Most places that have this climate are found at the outer margins of the tropical zone, but occasionally an inner-tropical location (e.g., San Marcos, Antioquia, Colombia) also qualifies.
Distribution of Savanna Climate

Q. With reference to the water on the planet Earth, consider the following statements:

1. The amount of water in the rivers and lakes is more than the amount of groundwater.
2. The amount of water In polar ice caps and glaciers is more than the amount of groundwater.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Answer: (b) 2 only

Distribution of water on the surface of the earth:
ReservoirPercentage of the total
Ice caps and glaciers2.05
Soil moisture0.005
Streams and Rivers0.0001
  • Water in groundwater is 0.62% while in lakes and rivers it is 0.008 (Salt lakes) + 0.009(freshwater lakes) + 0.0001(rivers)=0.0171.
  • Water in polar ice caps and glaciers is 2% while in groundwater it is 0.62%.
  • Earth’s surface is covered with 29% of land and 71% of water. Out of 71% of water, 97% of water is saltwater which is present in oceans, seas, and saltwater lakes.
  • Remaining 3% of water present on the land is freshwater which is present in the form of glaciers, ice caps, groundwater, lakes, rivers, and in the atmosphere as water vapor.
  • Out of 3% of freshwater, 2.5% of the earth’s freshwater cannot be used because it is locked up in glaciers, polar ice caps, atmosphere, and soil; highly polluted, or lies too far under the earth’s surface to be extracted at an affordable cost.
    • Of the total freshwater, 69% resides in glaciers, 30% undergroundand less than 1% is located in lakes, rivers, and swamps. Thus, the amount of water in rivers and lakes is less than amount of groundwater.  

Q. Consider the following statements:

1. Moringa (drumstick tree) is a leguminous evergreen tree.
2. Tamarind tree is endemic to south Asia.
3. In India, most of the tamarind is collected as minor forest produce.
4. India exports tamarind and seeds of moringa.
5. Seeds of moringa and tamarind can be used in the production of biofuels.

Which of the statements given above are correct?

(a) 1, 2, 4 and 5
(b) 3, 4 and 5
(c) 1, 3 and 4
(d) 1,2, 3 and 5

Answer: (b) 3, 4 and 5

Moringa (drumstick tree):
  • Moringa oleifera is a plant that is often called the drumstick tree, the miracle tree, the ben oil tree, or the horseradish tree.
  • Moringa has been used for centuries due to its medicinal properties and health benefits. It also has antifungal, antiviral, antidepressant, and anti-inflammatory properties.
  • It can be evergreen or semi-deciduous. Because of which is extensively being grown in semiarid regions in India.
​Tamarind Tree:
  • Tamarind (Tamarindus indica) is a leguminous tree bearing edible fruit that is indigenous to tropical Africa.
  • It is native to Africa or Indian-sub continent and grown in Southeast Asia and Africa as well.
  • Most of the tamarind is collected as minor forest produce.
  • India is one of the largest exporters of both Tamarind and Seed of Moringa. 

Q. The black cotton soil of India has been formed due to the weathering of

(a) Brown forest soil
(b) Fissure volcanic rock
(c) Granite and schist
(d) Shale and limestone

Answer: (b) Fissure volcanic rock

Black Soil:
  • The parent material for most of the black soil is the volcanic rocks that were formed in the Deccan Plateau (Deccan and the Rajmahal trap).
  • A typical black soil is highly argillaceous [Geology (of rocks or sediment) consisting of or containing clay] with a large clay factor, 62 per cent or more.
  • In general, black soils of uplands are of low fertility while those in the valleys are very fertile.
  • The black colour is due to the presence of a small proportion of titaniferous magnetite or iron and black constituents of the parent rock.
  • The black soil is highly retentive of moisture. It swells greatly on accumulating moisture. Strenuous effort is required to work on such soil in the rainy season as it gets very sticky.
  • Black soils are spread mostly across interior Gujarat, Maharashtra, Karnataka, and Madhya Pradesh on the Deccan lava plateau and the Malwa Plateau, where there is both moderate rainfall and underlying basaltic rock

Q. How is permaculture farming different from conventional chemical farming?

1. Permaculture farming discourages monocultural practices but in conventional chemical farming, monoculture practices are predominant.
2. Conventional chemical farming can cause increase in soil salinity but the occurrence of such phenomenon is not observed in permaculture farming.
3. Conventional chemical farming is easily possible in such regions.
4. Practice of mulching is very important in permaculture farming but not necessarily so in conventional chemical farming.

Select the correct answer using the code given below.

(a) 1 and 3
(b) 1, 2 and 4
(c) 4 only
(d) 2 and 3

Answer: (b) 1, 2 and 4

  • The philosophy behind permaculture was developed in 1970s in Australia by Bill Mollison and David Holmgren. The land is called Tamera, the name given to these 330 acres in southern Portugal by a community of 30 people who moved here from Germany in 1995. Through simple practices of digging swales (ditches) and creating water retention spaces, Tamera’s ecology experts have transformed an area on the brink of desertification.  
  • Permaculture tries to look at a piece of land in a holistic manner, integrating every animal and plant living on it, and combining that with social structures designed to foster long-lasting agriculture as well. Each element of a food cycle is broken down into what it requires and what it contributes, and then each element is pieced together to form a dynamically self-supporting whole.
  • Permaculture is a totally integrated design system that’s modelled on nature. Permaculture farming promotes multicropping and integrated farming systems. Agroforestry is its example.  
  • High-density crops and the use of single crops over large expanses of land strips away necessary nutrients as generations pass, eventually leaving the land barren. So Permaculture discourages monoculture.
  • At the same time, artificial fertilizers can build up salts over time, making the soil inhospitable to plants.
  • Mulching is an important practice in permaculture.
  • Chemical farming
    • Chemical farming is more suitable for monoculture cropping due to use of crop specific inputs like irrigation, chemical fertiliser and harvesting methods.  
    • Chemical farming is based on intense use of inputs like Chemical fertilizers and irrigation that make the soil less fertile over time, thus restricting its practise in semi-arid region. Thus, conventional farming is not suitable for semi-arid regions.  

Q. With reference to ‘palm oil’, consider the following statements:

(a) The palm oil tree is native to Southeast Asia.
(b) The palm oil is a raw material for some industries producing lipstick and perfumes.
(c) The palm oil can be used to produce biodiesel.

Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Answer: (b) 2 and 3 only

Palm Oil tree:
  • ​Palm oil is derived from the oil palm tree, which is native to West Africa and grows best in tropical climates with abundant water. It was imported into SE Asia in the mid 19th century.
  • Oil palm flourishes in the humid tropics and produces a high yield when grown 10 degrees north and south of the equator.
  • Palm Sludge Oil (PSO) is the floating residual oil that separated during the initial stage of POME discharge to the pond. The PSO is currently being categorised under sludge oil as it exhibits high Free Fatty Acids (FFA) and very low Deterioration of Bleachability Index (DOBI) values.
  • Due to the inferior quality of PSO, this residual oil cannot be used directly as a food source but normally being used for low-grade laundry soap formulation to substitute palm fatty acids distillate.
  • Conventionally, Volatile short-chain fatty Acid (VSCFA) has been widely used as raw material in the fragrant industry for the production of perfume via the esterification process.
  • If refined, the PSO can be applied directly as boiler fuel, raw material for biodiesel production.
  • The Palm oil can be used to produce biodiesel. It can be used in compression ignition engines, i.e., diesel engines without any modifications. It refers to methyl esters derived from palm oil through a process known as ‘transesterification’. 
Palm Oil tree

Q. With reference to the Indus River system, of the following four rivers, three of them pour into one of the which joins the Indus direct. Among the following, which one is such river that joins the Indus direct?

(a) Chenab
(b) Jhelum
(c) Ravi
(d) Sutlej

Answer: (d) Sutlej

Indus River System
  • The Indus system comprises the main Indus, Jhelum, Chenab, Ravi, Beas and Sutlej. The basin is mainly shared by India and Pakistan with a small share for China and Afghanistan.
  • Jhelum and Ravi join Chenab, Beas joins Sutlej, and then Sutlej and Chenab join to form Panjnad, 10 miles north of Uch Sharif in Muzaffar Garh district.
  • The combined stream runs southwest for approximately 44 miles and joins the Indus River at Mithankot.
  • Sutlej River:
    • The ancient name of the Sutlej River is Zaradros (Ancient Greek) Shutudri or Shatadru (Sanskrit).
    • It is the longest of the five tributaries of the Indus River that give Punjab (meaning “Five Rivers”) its name.
    • It rises on the north slope of the Himalayas in Lake La’nga in southwestern Tibet.
Major Tributaries of Indus River

Q. With references to India, Didwana, Kuchaman, Sargol, and khatu are the names of

(a) Glaciers
(b) Mangrove areas
(c) Ramsar sites
(d) Saline lakes

Answer: (d) Saline lakes

  • Playas are small lakes with flat floors and undrained basins in which water collects after rains and evaporates quickly are called playas.
  • ​Didwana is a playa. Other such playas are the Kuchaman, the Sargol and the Khatu lakes.
  • Didwana is a town in the Nagaur district of Rajasthan. It also has a famous Didwana saltwater lake of Rajasthan. The lake is about 4 km in length and with 3 km breadth, The depression is surrounded on all sides by sandhills, except to the west. The depression bed shows the presence of black clay and in appearance is similar to that of the Sambhar lake.
  • Kuchaman lake is a continental saline lake located around Kuchaman city, Nagaur District, Rajasthan

Q. Consider the following Rivers:

1. Brahmani
2. Nagavali
3. Subarnarekha
4. Vamsadhara

Which of the above rise from the Eastern Ghats?

(a) 1 and 2
(b) 2 and 4
(c) 3 and 4
(d) 1 and 3

Answer: (b) 2 and 4

  • The Brahmani is a major seasonal river in the Odisha state of eastern India. 
  • The Brahmani is formed by the confluence of the Sankh and South Koel rivers near Rourkela.
  • Together with the river Baitarani, it forms a large delta before emptying into the Bay of Bengal at Dhamra.
  • The River Nagavali is also known as Langulya is one of the main rivers of Southern Odisha and Northern Andhra Pradesh States in India, between Rushikulya and Godavari basins.
  • Nagavali River originates in Kalahandi District, in eastern Ghats.
  • The Subarnarekha originates from the Ranchi Plateau in Jharkhand forming the boundary between West Bengal and Odisha in its lower course.
  • It joins the Bay of Bengal forming an estuary between the Ganga and Mahanadi deltas. Its total length is 395 km.
  • It is an east-flowing river that originates in the Kalahandi district of Odisha, Eastern Ghat, flows in Odisha, along its boundary with Andhra Pradesh and finally joins the Bay of Bengal at Kalingapatnam, Andhra Pradesh.
  • It is the main river of the north-eastern Andhra region and the Boddepalli Rajagopala Rao Project was constructed on it to meet the irrigation needs of the region.

Q. Among the following, which one is the least water-efficient crop?

(a) Sugarcane
(b) Sunflower
(c) Pearl millet
(d) Red gram

Answer: (a) Sugarcane

  • Sugarcane is the least water efficient crop. Among the given options, its water requirement is 1800-2200 mm/season which is highest
    • Sunflower’s water requirement was estimated at 672.4 mm/season. 
    • Pearl millet is a drought tolerant crop. Water requirement: 350 mm/season. 
    • Red gram uses about 250-400 mm/season of water.  
  • In terms of production, Sugarcane is the world’s largest crop.
  • Sugarcane belongs to Poaceae family of true grasses.
  • In India, Sugarcane is grown as a Kharif Crop.
  • It needs hot and humid climate with an average temperature of 21°C to 27°C.
  • 75-150 cm rainfall is favorable for sugar cane cultivation.
  • Irrigation needed for areas with lesser rainfall.
  • Sugarcane can grow in any soil which can retain moisture.
  • Ideal soil for sugarcane is deep rich loamy soil.
  • The soil needs to be rich in nitrogen, calcium and phosphorus but neither it should be neither too acidic nor too alkaline.
  • Crop water needed: 1500-2500 (mm/total growing period) and draught sensitivity is very High. Hence, sugarcane is the correct answer.

Q. Consider the following statements:

1. In the tropical zone, the western sections of the oceans are warmer than the eastern sections owing to the influence of trade winds.
2. In the temperate Zone, westerlies make the eastern sections of oceans warmer than the western sections

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 and 2

Answer: (c) Both 1 and 2

  • Warmer water is transported westward in the ocean by the Northeast trade winds in the Northern hemisphere of the tropical zone (as the figure given below shows). So, in tropical zones, the western section of ocean is warmer than eastern sections due to trade winds.  
  • Similarly, the Westerlies play an important role in carrying the warm, equatorial waters and winds to the western coasts of continents (that is eastern section of the Oceans in temperate zone). Thus, in temperate zones, westerlies make the eastern section of the ocean warmer than the western sections. 

Q. “Leaf litter decomposes faster than in any other biome and as a result, the soil surface is often almost bare. Apart from trees, the vegetation is largely composed of plant forms that reach up into the canopy vicariously, by climbing the trees or growing as epiphytes, rooted on the upper branches of trees.” This is the most likely description of

(a) Coniferous forest
(b) Dry deciduous forest
(c) Mangrove forest
(d) Tropical rain forest

Answer: (d) Tropical rain forest

Tropical rain forest:
  • The tropical rain forest is a forest with tall trees in a region of year-round high temperatures where an average of 50 to 260 inches of rain falls yearly.
  • Rain forests belong to the tropical wet climate group. The temperature in a rain forest rarely gets higher than 34°C or drops below 20°C, average humidity is between 77 and 88%. Rainfall is often more than 100 inches a year. There is usually a brief season of less rain. Almost all rainforests lie near the equator.
  • Many of the trees have straight trunks that don’t branch out.
  • The majority of the trees have a smooth, thin bark because there is no need to protect them from water loss and freezing temperatures.
  • It also makes it difficult for plant parasites to get a hold on the trunks.
  • The bark of different species is so similar that it is difficult to identify a tree by its bark.
  • Many trees can only be identified by their flowers.
  • The fertility of topsoil in rainforest regions is very poor. Torrential downpours wash out most of the topsoil nutrients.
  • The soil deteriorates rapidly with subsequent soil erosion and soil impoverishment.
  • The equatorial vegetation comprises a multitude of evergreen trees that yield tropical hardwood, e.g. mahogany, ebony, dyewoods etc.
  • In tropical rainforest biome, hot, moist atmosphere and all the dead plant material create the perfect conditions in which bacteria and other microorganisms can thrive. This leads to rapid decomposition of leaf litter material. The tropical rainforest is known for its dense canopies of vegetation that form three different layers.