[DAY 6] 60 DAY RAPID REVISION (RaRe) SERIES for UPSC Prelims 2023 – SCIENCE AND TECHNOLOGY, CURRENT AFFAIRS & CSAT TEST SERIES!

Solution: (d)

Explanation:

• Environment is everything around us including living organisms and non-living beings such as soil, air, water while ecosystem is a much broader term of which environment is a part of. Hence, statement 1 is incorrect.
• The primary difference between environment and ecosystem is that the environment relates to the immediate surroundings, whereas the ecosystem refers to a community of living species and their interactions with non-living elements of the environment. Hence, statement 2 is incorrect.
• Ecology is the study of the relationships between living organisms, including humans, and their physical environment; it seeks to understand the vital connections between plants and animals and the world around them. Hence, statement 3 is correct.

Solution: (b)

Explanation:

• It includes all living organisms on earth, inclusive of the dead organic matter produced by them. Hence, statement 1 is incorrect.
• The biosphere is absent at extremes of the North and South poles, the highest mountains and the deepest oceans since existing hostile conditions there do not support life (life is the characteristic feature of the biosphere). Hence, statement 2 is correct.
• Occasionally spores of fungi and bacteria do occur at a great height beyond 8,000 metres, but they are metabolically inactive, and hence represent only dormant life. Hence, statement 3 is incorrect.

Solution: (b)

Explanation:

• A grazing food chain is a food chain that starts with green plants as the main source of energy. Hence, statement 1 is correct.
• The food chainis a feeding hierarchy in which organisms in an ecosystem are grouped into trophic levels and are shown in a succession to represent the flow of food energy and the feeding relationships between them. The grazing food chain is present in both the terrestrial ecosystem (green plants) and the aquatic ecosystem (phytoplankton) as the primary source of energy.Hence, statement 2 is incorrect.
• The grazing food chain and the detritus food chain are linked to each other as the initial energy source for the detritus food chain is the waste materials and dead organic matter from the grazing food chain. Hence, statement 3 is incorrect .
• A detritus food chain is a food chain that starts with the dead remains of organisms(not green plants) as a main source of energy. Hence, statement 4 is incorrect

Solution: (c)

Explanation:

• Biomagnification is any concentration of a toxin, such as pesticides, in the tissues of tolerant organisms at successively higher levels in a food chain. Hence, statement 1 is incorrect.
• Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Hence, statement 2 is incorrect.
• Bioaccumulation often occurs in two ways, simultaneously: by eating contaminated food, and by absorption directly from water. This second case is specifically referred to as bioconcentration. Hence, statement 3 is correct.

Solution: (a)

Explanation:

• The process by which communities of plant and animal species in an area are replaced or changed into another over some time is known as ecological succession. Hence, statement 1 is correct.
• The climax community is stable, mature, more complex, and long-lasting. Hence, statement 2 is incorrect.
• The first plant to colonize an area is called the pioneer community.
• The final stage of succession is called the climax community.
• Secondary succession is the sequential development of biotic communities after the complete or partial destruction of the existing community. Hence, statement 3 is incorrect.
• Primary succession takes place an where no community has existed previously. The stage leading to the climax community is called the successional stage or seres. Each transitional community that is formed and replaced during succession is called a stage in succession or a seral community. Hence, statement 4 is incorrect.

Solution: (d)

Explanation:

• In general, species that have narrow or limited niches are considered to be specialist species. Koalas (Phascolarctos cinereus), which feed only on leaves from eucalyptus trees in Australia, are an example of a specialist species. Species with broader niches, like coyotes (Canis latrans) or raccoons (Procyon lotor), are considered generalists. No two species can have the exact same niche, otherwise they would be in direct competition for resources with one another. If this occurs, then one species will outcompete the other. If the losing species then does not adapt, it would lead to its extinction.Hence, statement 1 is correct.
• A habitat is a place of an ecosystem occupied by a particular organism. It reflects the living place of an organism. Hence, statement 2 is correct.
• The amount of space an animal uses on a regular basis is called its home range. Home ranges can stretch for many miles or they can be only a few feet. The size of a home range often depends on the size of an animal. Large animals, like the moose, need more space to survive than smaller animals like the chipmunk.Hence, statement 3 is correct.

Solution: (b)

Explanation:

• Ecotone is a transition zone between two biomes where organisms can survive. Ex: mangroves. Hence, statement 1 is incorrect.
• Ecoline can be defined as the zone where there is a continuous change from an ecosystem to another ecosystem when there is no proper boundary present between two different species present in that ecosystem. The flow that governs the ecoline is environmental gradients like changes in abiotic factors gradually.It is determined by physiochemical factors such as humidity, temperature, rainfall, and chemicals. Hence, statement 2 is correct.
• Note:Ecoline includes both ecosystem as well as the transition zone, whereas eco tone includes only transition zone.

Solution: (d)

Explanation:

• The Biotic Potential refers to the maximum rate at which a population can increase when resources are unlimited and environmental conditions are ideal.
• The Carrying Capacity refers to the maximum number of individuals of a given species that an area’s resources can sustain indefinitely without significantly depleting those resources. Hence, statement 1 is incorrect.
• The maximum number of a given species that can be sustained by resources in a given environment is the species’ carrying capacity, a concept often discussed alongside biotic potential. When a population is nearing its carrying capacity, the amount of resources used is equal to the amount of resources being produced. It is at this time individuals start competing; some may die and others may not reproduce because of the lack of resources. Conditions are no longer ideal and as a result, these individuals cannot reach their full biotic potential.Hence, statement 2 is incorrect .

Solution: (d)

Explanation:

• India continues to be the country with the highest number of producers (13,66,000), followed by Uganda (2,10,000), and Ethiopia (2,04,000). Most small-scale producers are certified in groups based on an internal control system. (FiBL Survey 2021) Hence, statement 1 is correct.
• Organic farming is in a nascent stage in India. About 2.30 million hectares of farmland was under organic cultivation as of March 2019. This is two per cent of the 140.1 million ha net sown area in the country. A few states have taken the lead in improving organic farming coverage, as a major part of this area is concentrated only in a handful of states. Madhya Pradesh tops the listwith 0.76 million ha of area under organic cultivation — that is over 27 per cent of India’s total organic cultivation area. Hence, statement 2 is correct.
• Organic agriculture is practiced in 187 countries, and 72.3 million hectares of agricultural land were managed organically by at least 3.1 million farmers. With the most organic agricultural land in Australia (35.69 m hectares) followed by Argentina (3.63 m hectares) and the Spain (2.35 m hectares). Hence, statement 3 is correct .

Solution: (d)

Explanation:

Solution: (a)

Explanation:

• The biogeochemical cycles in which the nutrients are replaced as fast as they are utilized are called the perfect nutrient cycle. Hence, statement 1 is correct.
• Most gaseous cycles are perfect nutrient cycles. Most sedimentary cycles are imperfect nutrient cyclese. some nutrients are lost from the cycles and get stored in the sediments. Hence, statement 2 is incorrect.
• The Nitrogen cycle and Carbon cycle are examples of the perfect nutrient cycle. Phosphorus cycle is totally sedimentary in nature.Hence, statement 3 is incorrect.

Solution: (c)

Explanation:

• The Ecotopes are the smallest ecologically distinct landscape features in a landscape mapping and classification system. As such, they represent relatively homogeneous, spatially explicit landscape functional units that are useful for stratifying landscapes into ecologically distinct features for the measurement and mapping of landscape structure, function and change.Like ecosystems, ecotopes are identified using flexible criteria, in the case of ecotopes, by criteria defined within a specific ecological mapping and classification system. Just as ecosystems are defined by the interaction of biotic and abiotic components, ecotope classification should stratify landscapes based on a combination of both biotic and abiotic factors, including vegetation, soils, hydrology, and other factors.. Hence, statement 1 is correct.
• The Ecosystem consists of a community of living beings and a physical environment both interacting and exchanging materials between them. Hence, statement 2 is correct.
• A population is a group of individuals of the same species living in the same area at the same time. Populations are dynamic and can change in size and composition over time.Hence, statement 3 is correct.

Solution: (b)

Explanation:

• The Edge Effect refers to a higher density of organisms and diversity of species within an ecotone. The organisms which occur most abundantly in this zone are called edge species. Hence, statement 1 is incorrect.
• The Ecological Amplitude refers to a specific range within which a species can tolerate ecological changes. Hence, statement 2 is correct.

Solution: (b)

Explanation:

• The flow of energy from producers(Autotrophs) to consumers(Heterotrophs )is called energy flow. Hence, statement 1 is incorrect.
• The energy flow is always unidirectional. The energy always flows from lower to higher trophic levels and it never flows in the reverse direction. Hence, statement 2 is correct.
• In a four level pyramid, only 0.1% of fixed energy ultimately reaches the top. In all ecosystem, first base level of pyramid will be occupied by producers, consumers occupy higher trophic levels. Energy is lost when it is transferred from one trophic level to the next. Approximately 10% of the stored energy of a trophic level could be transferred to the consumers of next level. Thus very less number of individuals could be supported at the top level. Hence, statement 2 is correct.

Solution: (a)

Explanation:

Limitations of Ecological Pyramid

• The saprophytes are not considered in any of the pyramids even though they form an important part of the various ecosystem. Hence, statement 1 is correct.
• These pyramids are applicable only to simple food chains, which usually do not occur naturally. Hence, statement 2 is incorrect.
• These pyramids do not deliver any concept in relation to variations in season and climate.
• They do not consider the possibility of the existence of the same species at different levels.
• More than one species may occupy multiple trophic levels as in case of the food web. Thus, this system does not take into account food webs. Hence, statement 3 is correct.

Solution: (c)

Explanation:

• Gross Primary Productivity refers to the amount of organic substance synthesized by the producers in unit time per unit area.It describes how much glucose is produced during photosynthesis.The value of GPP is always comparatively higher than NPP . Hence, statement 1 is correct .
• The Net Primary Productivity of an ecosystem is the available biomass for consumption by herbivores and carnivores. Net Primary Productivity = Gross Primary Productivity – Respiration losses (R). It describes how much glucose is produced excluding the amount of energy utilized for respiratory processes. The value of NPP is always comparatively lower than GPP. Hence, statement 2 is correct .

Solution: (c)

Explanation:

• The Food Web includes multiple interlinked food chains. Hence, statement 1 is incorrect.
• It is a representation of all possible paths of energy flow in an ecosystem. Hence, statement 2 is correct.
• It has more than one alternative for food for most of the organisms as a result it increases the chances of survival. Ex: Grass may serve as food for deer, rabbit, or cow.
• Food webs are dynamic and can change in response to changes in the environment, such as the introduction or removal of a species or changes in climate. Hence, statement 3 is incorrect.

Solution: (d)

Explanation:

• Nitrogen fixation is a process where nitrogen is converted into ammonia with the help of bacteria such as Clostridium and Rhodosprillium. Hence, statement 1 is correct.
• Ammonification converts organic nitrogenous matter from living organisms into ammonium. Hence, statement 2 is correct.
• Nitrate present in the soil is reduced to nitrogen by the process of denitrification.In the soil as well as oceans there are special denitrifying bacteria (Pseudomonas and Thiobacillus), which convert the nitrates/nitrites to elemental nitrogen.This nitrogen escapes into the atmosphere, thus completing the cycle. Hence, statement 3 is correct.

Solution: (d)

Explanation:

• The detritivores break down detritus into smaller particles in a process called fragmentation. Hence, statement 1 is incorrect.
• The bacterial and fungal enzymes degrade detritus into simpler inorganic substances in a process called catabolism. Hence, statement 2 is correct.
• The accumulation of a dark-colored amorphous substance called humus during decomposition in the soil in a process called humification. Hence, statement 3 is correct.

Solution: (a)

Explanation:

The question asks for an incorrect option.

Sulphur also has a small gaseous phase as sulphur dioxide, but is not considered a gaseous cycle because the biggest sulphur reservoir is the ocean.Thus the Sulphur Cycle is a sedimentary cycle. Hence, option a is incorrect.

Solution (c)

Explanation:

• Statement 1 – Incorrect, The temple is attributed to king Narasimhadeva I of the Eastern Ganga dynasty. The 13^th Century temple is dedicated to Hindu Sun God Surya. The temple follows the traditional style of Kalinga architecture.
• Statement 2 – Correct, Out of the total 40 Indian sites listed in UNESCO’s world heritage sites, Sun temple in Konark is the only sun temple to be listed.
• Statement 3 – Incorrect, This temple was called the “Black Pagoda” in European sailor accounts as early as 1676 because it looked like a great tiered tower which appeared black. Similarly, the Jagannath Temple in Puri was called the “White Pagoda”. Both temples served as important landmarks for sailors in the Bay of Bengal.
• Statement 4 – Correct, The artwork inside the temple comprises of images from Shaktism, Shaivism and Vaishnavism. These include images of musicians and mythological narratives as well as sculptures of Hindu deities, including Durga in her Mahishasuramardini aspect killing the shape-shifting buffalo demon (Shaktism), Vishnu in his Jagannatha form (Vaishnavism), and Shiva as a (largely damaged) linga (Shaivism).

Solution (b)

Explanation:

• Statement 1 – Incorrect, The Rampa Rebellion of 1922, also known as the Manyam Rebellion, was a tribal uprising led by Alluri Sitarama Raju in Godavari Agency of Madras Presidency, British India. It was a violent rebellion which included raids on police stations, robbery and guerilla warfare.
• Statement 2 – Correct, Alluri had adopted aspects from the Non-cooperation movement, such as promoting temperance, and the boycott of colonial courts in favour of local justice, administered by panchayat courts, to attract people’s support
• Statement 3 – Correct, Lord Reading (1921 to 1926) was the viceroy during Rampa Rebellion.

Solution (d)

Explanation:

The ISRO System for Safe and Sustainable Space Operations & Management (IS4OM) is ISRO’s holistic approach to ensure the safety of space assets and sustaining the utilization of outer space for national development. S4OM facility will aid India in achieving its SSA (Space Situational Awareness) goals by providing a comprehensive and timely information of the Space environment to users.

Solution (c)

Explanation:

• Statement 1 – Correct, The Code of Criminal Procedure, 1973 does not define bail, although the terms bailable offence and non-bailable offence have been defined in section 2(a) of the Code.
• Statement 2 – Incorrect, Non-bailable offences are cognisable, which enables the police officer to arrest without a warrant. In such cases, a magistrate would determine if the accused is fit to be released on bail.
• Statement 3 – Correct, A Bailable offence is defined as an offence which is shown as bailable in the First Schedule of the Code or which is made bailable by any other law, and non-bailable offence means any other offence.

Solution (a)

Explanation:

• Statement 1 – Correct, under the scheme, financial assistance in the form of grant-in-aid is provided to Central/State Government owned agencies (or their Joint Ventures with major stake-holding by them) for setting up or up-grading export infrastructure in States/UTs.
• Statement 2 – Incorrect, The Department of Commerce, Government of India is implementing the Trade Infrastructure for Export Scheme (TIES) w.e.f. FY 2017-18 with the objective of assisting Central and State Government agencies in the creation of appropriate infrastructure for growth of exports.

Solution (b)

Explanation:

3-digit numbers have to be formed using the digits 1 to 9.

Here, the order of the digits matters.

Therefore, there will be as many 3-digit numbers as there are permutations of 9 different

digits taken 3 at a time.

Therefore, required number of 3-digit numbers = 3P3 = 9!/(9-3)!

= 9*8*7*6!/6! = 504

Solution (c)

Explanation:

Since there are five routes for going from station A to station B

So number of ways of going from A to B is 5

And there are four routes for going from B to C, so the number of ways of going from B to C is 4

Thus using multiplication rule, number of ways of going from A to C via B is, 5×4=20

Solution (c)

Explanation:

2 different vowels and 2 different consonants are to be selected from the English alphabet.

Since there are 5 vowels in the English alphabet, number of ways of selecting 2 different vowels from the alphabet = 5C 2 = 5!/2!3! = 10

Since there are 21 consonants in the English alphabet, number of ways of selecting 2 different consonants from the alphabet = 21C 2 = 21!/19!2! = 210

Therefore, number of combinations of 2 different vowels and 2 different consonants = 10 × 210

= 2,100

Each of these 2,100 combinations has 4 letters, which can be arranged among themselves in 4! Ways.

Therefore, required number of words = 2100 × 4! = 50,400

Solution (a)

Explanation:

It is given that the question paper consists of 12 questions divided into two parts – Part I and

Part II, containing 5 and 7 questions, respectively.

A student has to attempt 8 questions, selecting at least 3 from each part.

This can be done as follows.

(a) 3 questions from part I and 5 questions from part II

(b) 4 questions from part I and 4 questions from part II

(c) 5 questions from part I and 3 questions from part II

3 questions from part I and 5 questions from part II can be selected in 5C 3 * 7C 5 ways

4 questions from part I and 4 questions from part II can be selected in 5C 4 * 7C 4 ways.

5 questions from part I and 3 questions from part II can be selected in 5C 5 * 7C 3 ways.

Thus, required number of ways of selecting questions =[5C3 * 7C5] *[5C4 * 7C4 ]* [5C5 * 7C3]

On solving, we get 420 ways

Solution (c)

Explanation:

Option a: This is not implied. The study shows that those who fared well in intelligence tests

were four times more likely to develop bipolar disorder. However, this does not imply that

the converse is true.

Option b: Again, this statement is not implied. Correlation does not imply causation.

Option c: This is clearly inferred from the paragraph.

Option d: It cannot be concluded from what is stated in the study that this is true. While

there is a correlation between genius and mental illness, it does not imply one causes the

other.