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General Science and Technology

222 questions

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Question 81Question →

Arrange the following cellular events occurring during Prophase I of Meiosis I in the correct chronological order from beginning to end:

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Answer

The correct chronological order of events during meiotic Prophase I is: (1) Chromatin condensation (Leptotene), (2) Synaptonemal complex formation and pairing (Zygotene), (3) Recombination nodules and crossing over (Pachytene), (4) Dissolution of synaptonemal complex and visible chiasmata (Diplotene), and (5) Terminalisation of chiasmata and nuclear envelope breakdown (Diakinesis).
Prophase I of meiosis consists of five sequential stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis. Chromatin condensation initiates in Leptotene, followed by homologous pairing and synaptonemal complex formation in Zygotene. Recombination modules catalyze crossing over in Pachytene. Dissolution of the synaptonemal complex in Diplotene reveals chiasmata, which then undergo terminalisation alongside nuclear membrane breakdown in Diakinesis.

Step-by-Step Solution

1
Identify the first substage of Prophase I (Leptotene).
Chromatin condenses into long thread-like structures visible under light microscopy.
Compaction of genetic material is the prerequisite step before homologous chromosome pairing can take place.
2
Identify the second substage of Prophase I (Zygotene).
Homologous chromosomes align side-by-side (synapsis) mediated by the zipper-like synaptonemal complex.
Stabilizing pair structure is required to position non-sister chromatids in close proximity for recombination.
3
Identify the third substage of Prophase I (Pachytene).
Recombination nodules form and non-sister chromatids undergo enzymatic reciprocal crossing over.
Genetic variation is introduced through physical exchange of DNA segments between paired homologues.
4
Identify the fourth substage of Prophase I (Diplotene).
The synaptonemal complex degrades, causing homologues to separate except at points of crossing over (chiasmata).
Desynapsis allows structural visualization of the X-shaped chiasmata locations.
5
Identify the fifth substage of Prophase I (Diakinesis).
Chiasmata shift toward the ends of chromosomes (terminalisation), the nucleolus degrades, and the nuclear envelope disintegrates.
Prepares the bivalent chromosomes for alignment along the metaphase plate in Meiosis I.

Key Concept

Substages and Molecular Events of Meiotic Prophase I
Question 82Question →

Vinegar is widely used in household cooking, food preservation, and pickling to prevent food spoilage. Which organic acid is the primary active component present in household vinegar?

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Answer: Acetic acid

Answer

Acetic acid is the primary constituent of household vinegar.
Acetic acid (CH3COOHCH_3COOH), also known systematically as ethanoic acid, is produced via bacterial fermentation of ethanol and forms the essential acidic ingredient (usually 4–8% by volume) in commercial and household vinegar.

Step-by-Step Solution

1
Identify the chemical composition of household vinegar.
Household vinegar is a dilute aqueous solution consisting mainly of acetic acid (CH3COOHCH_3COOH) in water.
Fermentation of ethanol by acetic acid bacteria yields acetic acid, which provides vinegar with its characteristic sour taste and preservative qualities.

Key Concept

Chemical compounds in everyday household use
Question 83Question →

With reference to India's Integrated Guided Missile Development Programme (IGMDP), which of the following missiles was developed specifically as a surface-to-air missile system?

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Answer: Akash

Answer

Akash
Akash was developed under the Integrated Guided Missile Development Programme (IGMDP) as a medium-range surface-to-air missile system capable of targeting aircraft, helicopters, and drones.

Step-by-Step Solution

1
Identify the primary missiles developed under India's Integrated Guided Missile Development Programme (IGMDP).
The five core missiles developed under IGMDP are Prithvi, Agni, Trishul, Akash, and Nag.
Recognizing the core missile list is the first step in identifying their roles.
2
Classify each missile by its operational role and deployment domain.
Prithvi and Agni are surface-to-surface ballistic missiles, Nag is an anti-tank missile, and Akash (along with Trishul) is a surface-to-air missile.
Matching the operational role confirms which missile is dedicated to air defense against surface targets.

Key Concept

Integrated Guided Missile Development Programme (IGMDP) Classifications
Estimated Time:45s
Question 84Question →

Consider the following statements regarding India's Three-Stage Nuclear Power Programme:

1. Stage I utilizes Pressurised Heavy Water Reactors (PHWRs) fueled by natural uranium.
2. Stage II involves Fast Breeder Reactors (FBRs) designed to use plutonium derived from Stage I to breed fissile material from thorium.
3. Stage III envisions Advanced Heavy Water Reactors (AHWRs) fueled primarily by Uranium-235.

Which of the statements given above is/are correct?

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Answer: 1 and 2 only

Answer

1 and 2 only
The statements describing Stage I (PHWRs utilizing natural uranium) and Stage II (Fast Breeder Reactors converting Thorium to fissile material) are factually accurate. The third statement is incorrect because Stage III is designed around the Thorium and Uranium-233 fuel cycle, not Uranium-235.

Step-by-Step Solution

1
Evaluate Statement 1 regarding Stage I reactors and fuel.
Statement 1 is correct. Stage I uses Pressurised Heavy Water Reactors (PHWRs) fueled by natural uranium, which produces electricity and fissile Plutonium-239 as a byproduct.
Natural uranium primarily consists of Uranium-238, which transmutes into Plutonium-239 during reactor operations.
2
Evaluate Statement 2 regarding Stage II reactors and fuel breeding.
Statement 2 is correct. Stage II employs Fast Breeder Reactors (FBRs) fueled by Plutonium-239 with a Thorium-232 blanket to breed Uranium-233.
Fast Breeder Reactors produce more fissile material than they consume, enabling the transition to thorium-based reactors.
3
Evaluate Statement 3 regarding Stage III reactor fuel composition.
Statement 3 is incorrect. Stage III utilizes Advanced Heavy Water Reactors (AHWRs) based on the Thorium-232 and Uranium-233 fuel cycle, not Uranium-235.
India possesses vast reserves of Thorium, making Uranium-233 (bred from Thorium) the target fuel for Stage III rather than rare imported Uranium-235.

Key Concept

India's Three-Stage Nuclear Power Programme
Question 85Question →

Regarding human infectious diseases, their causative agents, and transmission mechanisms, which of the following statements are correct?

Select all that apply

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Answer: Lymphatic filariasis is a parasitic infection caused by microscopic filarial worms such as WuchereriaWuchereria bancroftibancrofti, primarily transmitted to humans through the bites of infected mosquitoes.; Leptospirosis is a bacterial zoonotic disease caused by spirochetes of the genus LeptospiraLeptospira, commonly contracted through exposure to water or soil contaminated with the urine of infected animals.

Answer

The correct statements are the ones describing Lymphatic Filariasis as a filarial worm infection transmitted by mosquitoes and Leptospirosis as a bacterial zoonotic disease caused by LeptospiraLeptospira spirochetes.
The statements correctly identifying Lymphatic Filariasis (filarial worm transmitted by mosquito vectors) and Leptospirosis (bacterial spirochete infection spread via urine-contaminated water/soil) accurately reflect established epidemiological and physiological facts.

Step-by-Step Solution

1
Analyze the etiology and transmission of Lymphatic Filariasis and Leptospirosis.
Lymphatic Filariasis is a parasitic worm infection (WuchereriaWuchereria bancroftibancrofti) transmitted by mosquitoes. Leptospirosis is a bacterial infection (LeptospiraLeptospira) contracted via exposure to contaminated animal urine.
Both descriptions accurately match the pathogen classification and primary vector/route of transmission.
2
Evaluate the statements regarding Rabies and Chikungunya.
Rabies is caused by a Lyssavirus (not ClostridiumClostridium tetanitetani). Chikungunya is caused by an Alphavirus transmitted by AedesAedes mosquitoes (not a protozoan transmitted by sandflies).
Identifying pathogen type (viral vs bacterial vs protozoan) and vector species shows both statements conflate distinct disease etiologies.

Key Concept

Classification of infectious human diseases by pathogen type (bacterial, viral, helminthic) and vectors
Question 86Question →

With reference to human infectious diseases, vector transmission, and pathogen classification, consider the following statements:

1. Japanese Encephalitis is caused by a flavivirus and is transmitted primarily to humans by infected CulexCulex mosquitoes, with pigs acting as key amplifying hosts.
2. Lyme disease is a bacterial infection caused by the spirochete Borrelia burgdorferiBorrelia\ burgdorferi, transmitted through the bite of infected hard-bodied IxodesIxodes ticks.
3. Chagas disease (American Trypanosomiasis) is caused by the protozoan parasite Trypanosoma cruziTrypanosoma\ cruzi and is primarily transmitted by triatomine bugs.

Which of the statements given above are correct?

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Answer: 1, 2, and 3

Answer

Statements 1, 2, and 3 are all correct.
All three statements accurately describe the etiology and transmission dynamics of their respective diseases: Japanese Encephalitis is flaviviral (CulexCulex-borne with pig amplifying hosts), Lyme disease is bacterial (Borrelia burgdorferiBorrelia\ burgdorferi via IxodesIxodes ticks), and Chagas disease is protozoan (Trypanosoma cruziTrypanosoma\ cruzi via triatomine bugs).

Step-by-Step Solution

1
Evaluate Statement 1 regarding Japanese Encephalitis.
Statement 1 is correct. Japanese Encephalitis is a viral zoonotic disease caused by a single-stranded RNA virus of the genus FlavivirusFlavivirus. It is transmitted by CulexCulex mosquitoes (primarily Culex tritaeniorhynchusCulex\ tritaeniorhynchus), where domestic pigs and wild wading birds serve as main amplifying hosts.
Verifying the viral etiology, mosquito vector genus, and animal reservoir hosts.
2
Evaluate Statement 2 regarding Lyme disease.
Statement 2 is correct. Lyme disease is a bacterial zoonosis caused by the obligate spirochete Borrelia burgdorferiBorrelia\ burgdorferi (and related species), transmitted to humans via bites from infected black-legged ticks of the genus IxodesIxodes.
Verifying the bacterial nature of the spirochete and the tick vector.
3
Evaluate Statement 3 regarding Chagas disease.
Statement 3 is correct. Chagas disease (American Trypanosomiasis) is caused by the flagellated protozoan parasite Trypanosoma cruziTrypanosoma\ cruzi, vector-borne transmitted through the feces of blood-sucking triatomine bugs ('kissing bugs').
Verifying the protozoan pathogen classification and insect vector.

Key Concept

Pathogen classification (viral vs. bacterial vs. protozoan) and vector biology of human infectious diseases
Question 87Question →

Consider the following statements regarding optical phenomena observed in daily life:

1. Polarized sunglasses effectively reduce glare from horizontal surfaces such as water or asphalt because light reflected at Brewster's angle is predominantly horizontally polarized.
2. The white appearance of clouds, as opposed to the blue color of a clear sky, is attributed to Mie scattering by water droplets that scatter all visible wavelengths almost equally.
3. In the formation of a primary rainbow, sunlight undergoes two internal reflections and two refractions inside a raindrop, resulting in an inverted color sequence relative to a secondary rainbow.

Which of the statements given above is/are correct?

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Answer: 1 and 2 only

Answer

Statements 1 and 2 are correct.
The option stating '1 and 2 only' is correct. Glare reduction in polaroids relies on blocking horizontally polarized light reflected off flat surfaces (Statement 1). Clouds appear white because large droplet diameters cause Mie scattering, which scatters all colors of light equally (Statement 2). Statement 3 is incorrect because a primary rainbow is formed by a single internal reflection combined with two refractions inside raindrops, whereas a secondary rainbow involves two internal reflections.

Step-by-Step Solution

1
Analyze Statement 1 regarding glare and polarization.
Statement 1 is TRUE.
When unpolarized light strikes a smooth horizontal reflecting surface (like water or wet roads) near Brewster's angle, the reflected light becomes polarized parallel to the surface (horizontally polarized). Polarized sunglasses contain vertically oriented polarizing filters that absorb this horizontally polarized light, effectively eliminating glare.
2
Analyze Statement 2 regarding cloud color and scattering type.
Statement 2 is TRUE.
Rayleigh scattering occurs when scattering particles are much smaller than the wavelength of light (d≪λ d \ll \lambda), selectively scattering shorter blue wavelengths. In clouds, water droplets are significantly larger than light wavelengths (d≥λd \ge \lambda), triggering Mie scattering, which scatters all visible light wavelengths nearly equally, causing clouds to appear white.
3
Analyze Statement 3 regarding rainbow optics.
Statement 3 is FALSE.
A primary rainbow is formed when sunlight enters a spherical raindrop, undergoes refraction upon entry, one internal reflection at the back of the droplet, and a second refraction upon exit (1 reflection, 2 refractions). A secondary rainbow involves two internal reflections and two refractions (2 reflections, 2 refractions), which also makes it fainter and causes its color order (red inside, violet outside) to be reversed compared to the primary rainbow.

Key Concept

Optical Phenomena in Daily Life (Polarization, Mie Scattering, and Rainbow Internal Reflection)
Estimated Time:2m 0s
Question 88Question →

Arrange the following stages of India's Three-Stage Nuclear Power Programme in their correct sequential order of implementation, starting from the initial stage to the final stage.

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Answer

The correct sequence of India's Three-Stage Nuclear Power Programme is: Pressurised Heavy Water Reactors (PHWRs) using natural uranium, followed by Fast Breeder Reactors (FBRs) using plutonium, and culminating in Advanced reactors utilizing Thorium-232 and Uranium-233.
India's nuclear power programme was envisioned in three sequential stages to overcome natural uranium constraints and leverage abundant domestic thorium. Stage 1 employs Pressurised Heavy Water Reactors (PHWRs) using natural uranium to yield power and plutonium-239. Stage 2 deploys Fast Breeder Reactors (FBRs) using plutonium-239 to breed more plutonium and convert Thorium-232 to Uranium-233. Stage 3 employs reactors utilizing the Thorium-232 and Uranium-233 fuel cycle for ultimate self-sustained nuclear energy production.

Step-by-Step Solution

1
Identify the foundation of India's nuclear plan formulated by Dr. Homi J. Bhabha.
The plan begins with Pressurised Heavy Water Reactors (PHWRs) using natural uranium reserves to generate power and produce Plutonium-239.
Natural uranium is limited in India, making PHWRs the necessary initial fuel-building block.
2
Determine the second stage reactor technology.
Fast Breeder Reactors (FBRs) utilize the reprocessed Plutonium-239 from Stage 1 to breed additional fissile fuel and convert Thorium into Uranium-233.
Stage 2 acts as a bridge to convert Thorium into usable fissile material.
3
Determine the third and final stage reactor technology.
Advanced reactors (AHWRs/Thermal Breeders) utilize Thorium-232 and Uranium-233.
This stage enables complete utilization of India's extensive Thorium reserves to ensure long-term energy self-reliance.

Key Concept

India's Three-Stage Nuclear Power Programme
Question 89Question →

In the study of human health, vector-borne infectious diseases present complex interactions between pathogens, vectors, and human hosts. Which of the following statements regarding the etiology and vector transmission of these human diseases are correct?

Select all that apply

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Answer: Malaria is caused by protozoan parasites of the genus Plasmodium and is transmitted to humans through the bites of infected female Anopheles mosquitoes.; Chagas disease (American Trypanosomiasis) is caused by the protozoan parasite Trypanosoma cruzi and is transmitted primarily by triatomine bugs.

Answer

The statements asserting that Malaria is caused by Plasmodium protozoa transmitted by female Anopheles mosquitoes, and that Chagas disease is caused by Trypanosoma cruzi protozoa transmitted by triatomine bugs, are correct.
Malaria is accurately paired as a protozoan disease (PlasmodiumPlasmodium) transmitted by female AnophelesAnopheles mosquitoes. Chagas disease is accurately identified as a protozoan disease caused by Trypanosoma cruziTrypanosoma\ cruzi and transmitted via triatomine bugs (kissing bugs). Both descriptions correctly identify the pathogen kingdom/domain and vector.

Step-by-Step Solution

1
Analyze the etiology of Malaria.
Malaria is caused by protozoan parasites (PlasmodiumPlasmodium species) and vectored by female AnophelesAnopheles mosquitoes.
Verify the pathogen category (protozoan) and vector (female Anopheles mosquito).
2
Analyze the etiology of Human African Trypanosomiasis (Sleeping Sickness).
Sleeping Sickness is caused by protozoa (Trypanosoma bruceiTrypanosoma\ brucei), not bacteria.
Identify pathogen confusion in classifying protozoan infections as bacterial.
3
Analyze the etiology of Chagas disease.
Chagas disease is caused by the protozoan Trypanosoma cruziTrypanosoma\ cruzi and vectored by triatomine bugs.
Confirm both the protozoan nature of the pathogen and the correct insect vector.
4
Analyze the etiology of Plague.
Plague is caused by the bacterium Yersinia pestisYersinia\ pestis transmitted by rat fleas (Xenopsylla cheopisXenopsylla\ cheopis), not a virus or mosquito.
Distinguish bacterial zoonoses from viral or mosquito-borne diseases.

Key Concept

Vector-borne Human Pathogen Classification (Protozoan vs Bacterial vs Viral Pathogens and Vector Associations)
Question 90Question →

Typhoid fever is a common water-borne infectious disease in humans caused by Salmonella typhi. What type of pathogen is Salmonella typhi?

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Answer: Bacterium

Answer

Bacterium
Typhoid fever is caused by Salmonella typhi, which is a pathogenic Gram-negative bacterium that spreads through contaminated food and water, affecting the intestinal tract and bloodstream.

Step-by-Step Solution

1
Identify the causative organism for Typhoid fever
Salmonella typhi
Typhoid fever is contracted through contaminated food or water containing the organism Salmonella typhi.
2
Classify Salmonella typhi within biological taxonomy
Gram-negative bacterium
Salmonella typhi is a rod-shaped, Gram-negative, flagellated bacterium belonging to the family Enterobacteriaceae.

Key Concept

Human Disease Pathogen Classification
Estimated Time:45s
Question 91Question →

Arrange the following milestones in Indian defense technology in chronological order of their initial successful flight testing, starting from the earliest to the most recent:

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Answer

The correct chronological sequence is: (1) First flight test of the Prithvi surface-to-surface missile (1988), followed by (2) First flight test of the Akash surface-to-air missile (1990), then (3) First flight test of the BrahMos supersonic cruise missile (2001), and finally (4) First flight test of the Agni-V intercontinental ballistic missile (2012).
The correct chronological sequence is determined by the historical launch dates of each defense platform: Prithvi-I in 1988, Akash in 1990, BrahMos in 2001, and Agni-V in 2012.

Step-by-Step Solution

1
Identify the maiden flight test year of Prithvi.
Prithvi-I was first successfully flight-tested in February 1988 as part of the IGMDP.
Establishes the starting point for India's tactical missile program.
2
Identify the maiden flight test year of Akash.
Akash surface-to-air missile underwent its first flight test in 1990.
Places Akash after Prithvi in the development timeline of IGMDP missiles.
3
Identify the maiden test year of BrahMos.
BrahMos supersonic cruise missile was first test-fired in June 2001.
Establishes the early 2000s milestone for joint tactical cruise missile technology.
4
Identify the maiden flight test year of Agni-V.
Agni-V ICBM completed its maiden flight test in April 2012.
Marks the long-range intercontinental strategic missile milestone as the most recent of the group.

Key Concept

Chronology of Indian defense technology and missile program development milestones.
Question 92Question →

Match the everyday physical applications in List-I with their underlying physics principles in List-II, and identify the correct set of matching pairs.

Click a left item, then click its matching right item

Items

Working of hydraulic brakes in automobiles
Brilliant sparkling of a professionally cut diamond
Melting of a safety fuse wire during an electrical overload
Apparent loss of weight of a stone submerged in water

Matches

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Answer

The correct matching pairs connect: Hydraulic brakes with Pascal's Law; Brilliant sparkling of a diamond with Total internal reflection; Melting of a safety fuse with Joule heating effect; and Apparent loss of weight of a submerged stone with Archimedes' principle.
Each item in List-I correctly pairs with its foundational governing principle in List-II: hydraulic brakes rely on Pascal's law of fluid pressure; the brilliance of diamonds stems from total internal reflection; safety fuse wires function through Joule heating; and the buoyancy of submerged objects follows Archimedes' principle.

Step-by-Step Solution

1
Analyze the principle behind hydraulic brakes in vehicles.
Hydraulic systems use incompressible fluids to transmit fluid pressure undiminished to brake shoes.
This direct application of fluid statics corresponds to Pascal's Law.
2
Examine the optical mechanism causing a diamond to shine brilliantly.
Light entering the diamond strikes inner faces at angles greater than the critical angle, trapping light through repeated internal reflection.
This matches total internal reflection.
3
Evaluate the thermal effect of electric current in a safety fuse wire.
Excess current generates heat proportional to current squared (I2I^2), raising the wire's temperature to its melting point.
This describes the Joule heating effect of electric current.
4
Determine the principle explaining reduced apparent weight of submerged objects.
Water exerts an upthrust force equal to the weight of displaced water.
This is defined by Archimedes' principle of buoyancy.

Key Concept

Everyday Applications of Fundamental Physics Laws
Estimated Time:1m 15s
Question 93Question →

Match the physiological processes and agricultural biotechnology mechanisms listed in List-I with their corresponding biological functions or modes of action listed in List-II.

Click a left item, then click its matching right item

Items

Glomalin production by Vesicular-Arbuscular Mycorrhizal (VAM) fungi
Richmond-Lang effect mediated by Cytokinins
Systemic Acquired Resistance (SAR) pathway
RNA Interference (RNAi) technology in crop protection

Matches

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Answer

Glomalin production by VAM fungi matches with soil structure stabilization and phosphorus mobilization; the Richmond-Lang effect matches with delay of leaf senescence by maintaining protein synthesis and preventing chlorophyll loss; Systemic Acquired Resistance (SAR) matches with long-distance salicylic acid signaling and PR protein expression; and RNA Interference (RNAi) technology matches with sequence-specific mRNA degradation in target pests.
Each plant process is paired precisely with its established bio-molecular mechanism: VAM glomalin secretion stabilizes soil aggregates and improves phosphorus availability; cytokinin action responsible for the Richmond-Lang effect prevents chlorophyll breakdown; Systemic Acquired Resistance relies on salicylic acid-mediated induction of PR proteins; and pest-targeted RNAi acts via sequence-specific destruction of target pest mRNA.

Step-by-Step Solution

1
Identify the function of Vesicular-Arbuscular Mycorrhizal (VAM) fungi and glomalin in agricultural soil science.
Glomalin is a hydrophobic glycoprotein secreted by endomycorrhizal fungi (VAM) that promotes soil aggregate stability and assists in mobilizing immobile soil minerals, especially phosphorus.
Establishing the biochemical link between VAM fungi, glomalin secretion, and soil aggregate formation.
2
Analyze the plant physiological term 'Richmond-Lang effect'.
The Richmond-Lang effect specifically refers to cytokinin-induced preservation of chlorophyll content and inhibition of protein degradation, delaying leaf senescence.
Distinguishing hormone-specific physiological effects from general growth mechanisms.
3
Evaluate the mechanism of Systemic Acquired Resistance (SAR) in plant pathology.
SAR relies on endogenous salicylic acid accumulation following initial pathogen attack, leading to systemic synthesis of Pathogenesis-Related (PR) defense proteins throughout the plant.
Connecting plant immunity signaling pathways with systemic transcriptional activation.
4
Examine the mode of action of agricultural RNA Interference (RNAi) pest control.
RNAi technology uses engineered dsRNA sequences matching essential pest genes to cause gene silencing through targeted messenger RNA degradation.
Linking biotechnological gene expression tools to target-specific post-transcriptional silencing mechanisms.

Key Concept

Plant Physiological Signaling, Mycorrhizal Interactions, and Crop Biotechnology Applications
Question 94Question →

Arrange the main stages of mitotic cell division in eukaryotic cells in the correct chronological order from beginning to end:

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Answer

The correct chronological order of mitosis stages is Prophase, followed by Metaphase, Anaphase, and Telophase.
Mitosis proceeds in four main sequential phases: Prophase (condensation of chromatin and disintegration of the nuclear membrane), Metaphase (alignment of chromosomes at the cell equator), Anaphase (separation of sister chromatids to opposite poles), and Telophase (re-formation of nuclear membranes around daughter nuclei).

Step-by-Step Solution

1
Identify the initial phase of nuclear division.
Prophase is selected as the first stage.
Chromosomes must condense and the nuclear envelope disintegrates to allow spindle attachment.
2
Identify the phase of alignment.
Metaphase is selected as the second stage.
Spindle fibers align chromosomes along the metaphase plate.
3
Identify the phase of chromatid separation.
Anaphase is selected as the third stage.
Sister chromatids are pulled apart toward opposite poles of the cell.
4
Identify the final phase of nuclear reformation.
Telophase is selected as the fourth stage.
Decondensing chromosomes are enclosed by new nuclear membranes.

Key Concept

Chronological stages of Mitosis
Estimated Time:45s
Question 95Question →

With reference to beneficial microorganisms used as bio-fertilizers in agriculture, which of the following statements are correct?

Select all that apply

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Answer: Rhizobium forms a symbiotic association with leguminous plants to fix atmospheric nitrogen.; Azotobacter is a free-living, non-symbiotic nitrogen-fixing bacterium found in aerobic soils.

Answer

The statements confirming Rhizobium's symbiotic nitrogen fixation in legumes and Azotobacter's free-living nitrogen fixation in soils are correct.
Rhizobium forms symbiotic root nodules with legumes to convert atmospheric nitrogen into plant-usable forms, while Azotobacter operates as a free-living nitrogen fixer in soil. Both statements correctly describe their bio-fertilizing roles.

Step-by-Step Solution

1
Identify the symbiotic nitrogen fixer among bio-fertilizers.
Rhizobium establishes symbiotic root nodule associations with leguminous crops to fix atmospheric nitrogen.
This is a key biological nitrogen fixation process in agriculture.
2
Identify free-living nitrogen-fixing soil bacteria.
Azotobacter fixes atmospheric nitrogen freely without symbiotic root attachment.
It improves soil nitrogen levels independently in aerobic soil conditions.
3
Evaluate the roles of Azospirillum and Mycorrhizae.
Azospirillum is a beneficial associative bacterium, and Mycorrhizae are symbiotic fungi that enhance phosphate uptake, not pathogens or parasitic bacteria.
Both are bio-fertilizing organisms, not crop pathogens or parasitic bacteria.

Key Concept

Classification and biological functions of bio-fertilizers
Estimated Time:45s
Question 96Question →

Match List-I (Cybersecurity Concepts and Legal Provisions) with List-II (Core Features and Operational Principles) and select the correct matching pairs.

Click a left item, then click its matching right item

Items

Section 66F of Information Technology Act, 2000
Homomorphic Encryption
DNS Amplification Attack
Zero Trust Architecture (ZTA)

Matches

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Answer

The correct matching pairs Section 66F of the Information Technology Act, 2000 with statutory penalties for cyber terrorism affecting national sovereignty; Homomorphic Encryption with performing operations on ciphertexts without decryption; DNS Amplification Attack with exploiting open resolvers using spoofed IP addresses for DDoS traffic amplification; and Zero Trust Architecture with continuous authentication under the 'never trust, always verify' security model.
The correct pairings align each cybersecurity term and legal provision with its exact technical or statutory definition: Section 66F penalizes cyber terrorism against national security; Homomorphic Encryption enables computation over ciphertexts without prior decryption; DNS Amplification exploits open resolvers via spoofed requests to flood target systems; and Zero Trust Architecture eliminates implicit perimeter trust by enforcing continuous authentication.

Step-by-Step Solution

1
Identify the legal scope of Section 66F of the IT Act, 2000.
Section 66F focuses on Cyber Terrorism against national security, unity, and sovereign electronic infrastructure.
State PSC exams frequently test specific sections of the Indian IT Act, particularly provisions related to cyber terrorism (66F), privacy (66E), and identity theft (66C).
2
Evaluate the technical definition of Homomorphic Encryption.
Connect Homomorphic Encryption to performing computations on encrypted data without decrypting it first.
This cryptographic technique is essential for secure cloud computing and privacy-preserving data analytics.
3
Analyze the attack mechanism of DNS Amplification.
Associate DNS Amplification with reflection-based DDoS attacks using open recursive resolvers and IP spoofing.
Small UDP queries generate disproportionately large DNS response payloads sent to the victim's spoofed IP address.
4
Determine the operational paradigm of Zero Trust Architecture.
Link Zero Trust Architecture with continuous identity verification and zero implicit network perimeter trust.
ZTA assumes threats exist both outside and inside the corporate network boundary.

Key Concept

Information Security Frameworks, Cryptography, Cyber Attacks, and Statutory Laws
Estimated Time:2m 0s
Question 97Question →

Among the following infectious human diseases, which one is caused by a bacterial pathogen rather than a viral, protozoan, or fungal organism?

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Answer: Diphtheria

Answer

Diphtheria is the disease caused by a bacterial pathogen (Corynebacterium diphtheriae).
Diphtheria is an infection of the upper respiratory tract or skin caused by the Gram-positive bacterium Corynebacterium diphtheriae.

Step-by-Step Solution

1
Identify the causative organism for each disease listed in the choices.
Diphtheria is caused by Corynebacterium diphtheriae (bacterium); Yellow Fever is caused by Flavivirus (virus); Toxoplasmosis is caused by Toxoplasma gondii (protozoan); Histoplasmosis is caused by Histoplasma capsulatum (fungus).
Classifying each disease by its etiology helps isolate the bacterial disease.
2
Select the choice matching the bacterial pathogen requirement.
Diphtheria is the only bacterial infection among the options.
The question specifically asks for the disease caused by a bacterium.

Key Concept

Human Infectious Diseases and Pathogen Etiology
Question 98Question →

Which chemical compound is commonly known as 'Washing Soda' and used in domestic and industrial applications for softening hard water?

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Answer: Sodium carbonate decahydrate (Na2CO3⋅10H2ONa_2CO_3 \cdot 10H_2O)

Answer

Sodium carbonate decahydrate (Na2CO3⋅10H2ONa_2CO_3 \cdot 10H_2O)
The compound sodium carbonate decahydrate (Na2CO3⋅10H2ONa_2CO_3 \cdot 10H_2O) is commonly referred to as Washing Soda. It is extensively used in laundry cleaning and industrial processes to remove permanent hardness from water by precipitating calcium and magnesium ions.

Step-by-Step Solution

1
Identify the common chemical name 'Washing Soda'
Washing soda corresponds to hydrated sodium carbonate.
Chemical nomenclature assigns specific common names to hydrated salts used in daily life.
2
Determine the exact chemical formula
Na2CO3⋅10H2ONa_2CO_3 \cdot 10H_2O containing ten water molecules of crystallization.
Anhydrous sodium carbonate (Na2CO3Na_2CO_3) is known as soda ash; recrystallization from water gives washing soda.
3
Verify industrial application
It reacts with soluble Ca2+Ca^{2+} and Mg2+Mg^{2+} ions to form insoluble carbonates (CaCO3CaCO_3 and MgCO3MgCO_3), thereby removing permanent hardness.
Precipitating metal ions reduces soap consumption and prevents scum formation.

Key Concept

Chemical nomenclature and applications of sodium compounds in daily life
Question 99Question →

Match the specialized human physiological cell types listed in List-I with their primary secretory products and functions listed in List-II:

Click a left item, then click its matching right item

Items

Juxtaglomerular Cells
Chief (Peptic) Cells
Alpha Cells of Pancreatic Islets
Parafollicular (C) Cells of Thyroid

Matches

Show answer & explanation

Answer

Juxtaglomerular Cells correspond to Renin secretion; Chief Cells correspond to Pepsinogen secretion; Alpha Cells correspond to Glucagon secretion; Parafollicular C Cells correspond to Calcitonin secretion.
The cell types match precisely with their physiological functions: Juxtaglomerular cells secrete renin for blood pressure homeostasis; Chief cells secrete pepsinogen for gastric digestion; Alpha cells produce glucagon to elevate blood glucose; and Parafollicular C cells produce calcitonin to reduce blood calcium levels.

Step-by-Step Solution

1
Analyze renal endocrine function
Juxtaglomerular cells located in the kidney produce Renin, which converts angiotensinogen to angiotensin I.
Renin secretion is a key regulator of blood volume and arterial pressure.
2
Analyze gastric secretory mechanisms
Chief cells in gastric mucosa produce Pepsinogen, whereas Parietal cells secrete Hydrochloric Acid (HClHCl).
Pepsinogen must be activated by acidic pH to form pepsin.
3
Analyze endocrine pancreas regulation
Alpha cells secrete Glucagon (hyperglycemic factor), while Beta cells produce Insulin.
Glucagon maintains glucose homeostasis during fasting states.
4
Analyze thyroid calcium-regulating cells
Parafollicular C cells synthesize Calcitonin, which acts as an antagonist to Parathyroid Hormone (PTH).
Calcitonin decreases blood Ca2+Ca^{2+} concentration by promoting calcium incorporation into bone tissue.

Key Concept

Endocrine and exocrine cell differentiation and functional secretions in human organ systems
Question 100Question →

In the context of India's indigenous multi-layered Ballistic Missile Defence (BMD) programme developed by DRDO, which statement correctly distinguishes between exo-atmospheric and endo-atmospheric interception systems?

Show answer & explanation

Answer: Exo-atmospheric interceptors target incoming ballistic missiles outside Earth's atmosphere at high altitudes, whereas endo-atmospheric interceptors engage targets inside the atmosphere at lower altitudes.

Answer

Exo-atmospheric interceptors target incoming ballistic missiles outside Earth's atmosphere at high altitudes, whereas endo-atmospheric interceptors engage targets inside the atmosphere at lower altitudes.
The correct answer accurately states the core distinction in multi-layered missile defense architecture: exo-atmospheric interceptors engage incoming ballistic threats outside Earth's atmosphere in space, whereas endo-atmospheric interceptors engage threats that have re-entered the Earth's atmosphere.

Step-by-Step Solution

1
Analyze the operational regime of exo-atmospheric interception
Exo-atmospheric systems operate beyond Earth's atmosphere (typically above 50 km50\text{ km} altitude) where aerodynamic control surfaces do not work and reaction control systems (RCS) are required.
Understanding the physical environment outside the atmosphere is critical to defining exo-atmospheric engagement.
2
Analyze the operational regime of endo-atmospheric interception
Endo-atmospheric systems engage targets within Earth's atmosphere (typically below 30 km30\text{ km} altitude) utilizing atmospheric density and aerodynamic controls.
Distinguishing the lower altitude ceiling defines endo-atmospheric defense capability.
3
Map DRDO BMD interceptor missiles to their respective defense tiers
Prithvi Air Defence (PAD / Pradyumna) is designed for exo-atmospheric interception (50–80 km50\text{--}80\text{ km}), whereas Advanced Air Defence (AAD / Ashwin) is designed for endo-atmospheric interception (15–30 km15\text{--}30\text{ km}).
Verifying specific Indian defense assets confirms the correct conceptual differentiation.

Key Concept

Multi-tiered Ballistic Missile Defence Architecture (Exo-atmospheric vs Endo-atmospheric Interception)
Estimated Time:1m 30s
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