UPSC Science and technology PYQ 2025

 

14.

Consider the following pairs:

Plant — Description

I. Cassava : Woody shrub

II. Ginger : Herb with pseudostem

III. Malabar spinach : Herbaceous climber

IV. Mint : Annual shrub

V. Papaya : Woody shrub

How many of the above pairs are correctly matched?

(a) Only two

(b) Only three

(c) Only four

(d) All the five

Correct Answer:

(b) Only three

Explanation:

Extremely Difficult question and there are around 10% to 20% question in every upsc pre are like this.

Memorise them and move to next question best strategy for them.

Pair I — Cassava : Woody shrub — Correct ✅

Cassava (Manihot esculenta) is a perennial woody shrub.

It has a woody stem and tuberous roots.

Pair II — Ginger : Herb with pseudostem — Correct ✅

Ginger is a herb.

The visible “stem” is a pseudostem, formed by tightly packed leaf bases.

Pair III — Malabar spinach : Herbaceous climber — Correct ✅

Malabar spinach (Basella alba) is a soft-stemmed (herbaceous) climber.

It requires support and does not have woody tissue.

Pair IV — Mint : Annual shrub — Incorrect ❌

Mint (Mentha) is a perennial herb, not a shrub.

It has a soft, non-woody stem and regrows every year.

Pair V — Papaya : Woody shrub — Incorrect ❌

Papaya (Carica papaya) is a large herbaceous plant, often called a herbaceous tree.

Its stem is not woody; hence it is not a woody shrub.

Final Count:

Correct pairs → I, II, III

Total correct → Three

👉 Answer: (b) Only three

Memory Trick:

“Cassava–Wood, Ginger–Pseudo, Malabar–Climber; Mint & Papaya fool by size.”

13.

With reference to India's defence, consider the following pairs:

Aircraft type : Description

I. Dornier-228 : Maritime patrol aircraft

II. IL-76 : Supersonic combat aircraft

III. C-17 Globemaster III : Military transport aircraft

How many of the pairs given above are correctly matched?

(a) Only one

(b) Only two

(c) All the three

(d) None

Correct Answer:

(b) Only two

Explanation:

Pair I: Dornier-228 : Maritime patrol aircraft — Correct ✅

Dornier-228 is used by:

Indian Navy

Indian Coast Guard

Roles include:

Maritime patrol

Surveillance

Search and rescue

Hence, this pair is correctly matched.

Pair II: IL-76 : Supersonic combat aircraft — Incorrect ❌

IL-76 is:

A strategic heavy-lift military transport aircraft

It is used for:

Troop transport

Cargo transport

Disaster relief

It is neither supersonic nor a combat aircraft.

Hence, this pair is incorrectly matched.

Pair III: C-17 Globemaster III : Military transport aircraft — Correct ✅

C-17 Globemaster III is a:

Strategic military transport aircraft

Used by the Indian Air Force for:

Long-range heavy cargo transport

Rapid troop deployment

Hence, this pair is correctly matched.

Final Count:

Correct pairs → I and III

Total correct → Two

👉 Answer: (b) Only two

Memory Trick:

“Dornier guards seas, C-17 carries loads, IL-76 never fights.”

12.

Consider the following space missions:

I. Axiom-4

II. SpaDeX

III. Gaganyaan

How many of the space missions given above encourage and support micro-gravity research?

(a) Only one

(b) Only two

(c) All the three

(d) None

✅ Correct Answer (Revised):

(c) All the three

Explanation :

Statement I: Axiom-4 — Correct ✅

Axiom-4 is a human spaceflight mission to the International Space Station (ISS).

The ISS is a dedicated micro-gravity laboratory.

The mission explicitly carries experiments in medicine, biology, and material science under micro-gravity conditions.

Hence, Axiom-4 supports micro-gravity research.

Statement II: SpaDeX — Correct ✅ 

SpaDeX (Space Docking Experiment) is primarily a technology-demonstration mission.

However, it is linked with PSLV Orbital Experimental Module (POEM-4).

POEM-4 uses the spent fourth stage of PSLV as an orbital micro-gravity platform.

Experiments conducted include:

Plant growth and germination studies in micro-gravity

Radiation environment measurements affecting biological systems

👉 These are explicit scientific experiments in a micro-gravity environment, not incidental observations.

✔ Therefore, SpaDeX (via POEM-4) DOES support micro-gravity research.

Statement III: Gaganyaan — Correct ✅

Gaganyaan is India’s human spaceflight programme.

Human space missions inherently support:

Micro-gravity research in life sciences

Human physiology and space medicine

ISRO has officially planned micro-gravity experiments as part of the programme.

🧠 Memory Trick

“ISS, Humans, or POEM → Micro-gravity Research”

ISS mission → Axiom-4

Human mission → Gaganyaan

POEM platform → SpaDeX

11.

Consider the following statements:

I. Indian Railways have prepared a National Rail Plan (NRP) to create a future ready railway system by 2028.

II. ‘Kavach’ an Automatic Train Protection system developed in collaboration with Germany.

III. ‘Kavach’ system consists of RFID tags fitted on track in station section.

Which of the statements given above are not correct?

(a) I and II only

(b) II and III only

(c) I and III only

(d) I, II and III

✅ Answer :

(a) I and II only

Explanation :

Statement I — Not correct ❌

The National Rail Plan (NRP) is officially titled “National Rail Plan for India – 2030.”

Objective: to create a future-ready railway system by 2030, not 2028.

Hence, Statement I is incorrect.

Statement II — Not correct ❌

Kavach is an indigenously developed Automatic Train Protection (ATP) system.

Developed by Research Designs and Standards Organisation (RDSO) in collaboration with Indian industry.

It is NOT developed in collaboration with Germany.

Hence, Statement II is incorrect.

Statement III — Correct ✅

As per the image:

RFID (Radio Frequency Identification) tags are installed along the tracks.

These help Kavach in:

Tracking train position

Detecting safety issues

Therefore, Statement III is correct and should not be selected.

Final Logic:

Statements not correct → I and II

Correct statement → III

👉 Answer: (a) I and II only

Memory Trick (Refined):

“NRP = 2030, Kavach = Indian, RFID = Yes”

Wrong year → ❌

Foreign collaboration → ❌

RFID usage → ✅

10.

Consider the following statements:

Statement I:

Some rare earth elements are used in the manufacture of flat television screens and computer monitors.

Statement II:

Some rare earth elements have phosphorescent properties.

Which one of the following is correct in respect of the above statements?

(a) Both Statement I and Statement II are correct and Statement II explains Statement I

(b) Both Statement I and Statement II are correct but Statement II does not explain Statement I

(c) Statement I is correct but Statement II is not correct

(d) Statement I is not correct but Statement II is correct

Correct Answer:

(a) Both Statement I and Statement II are correct and Statement II explains Statement I

Explanation:

Statement I — Correct ✅

Rare earth elements such as Europium, Terbium, and Yttrium are widely used in flat-panel displays (LED/LCD/Plasma) and computer monitors.

Statement II — Correct ✅

Several rare earth elements exhibit phosphorescent / luminescent properties, meaning they can emit visible light when excited by electrons or photons.

Link between I and II (Explanation):

Flat screens work using phosphor materials to produce red, green, and blue colours.

Rare earth elements are ideal for this purpose because of their phosphorescent properties.

Hence, Statement II directly explains Statement I.

👉 Therefore, both statements are correct and Statement II explains Statement I.

Memory Trick:

“Rare earths glow → screens show”

→ Phosphorescence of rare earths explains their use in display screens.

9.

Consider the following statements regarding AI Action Summit held in Grand Palais, Paris in February 2025:

I. Co-chaired with India, the event builds on the advances made at the Bletchley Park Summit held in 2023 and the Seoul Summit held in 2024.

II. Along with other countries US and UK also signed the declaration on inclusive and sustainable AI.

Which of the statements given above is/are correct?

(a) I only

(b) II only

(c) Both I and II

(d) Neither I nor II

Correct Answer:

(a) I only

Explanation:

Statement I — Correct ✅

The AI Action Summit 2025 held at the Grand Palais in Paris was co-chaired by India and France and built on the advances from the earlier AI Safety Summit at Bletchley Park, UK, in 2023 and the AI Seoul Summit in 2024. 

Statement II — Incorrect ❌

At the Paris Summit, a joint Statement on Inclusive and Sustainable Artificial Intelligence for People and the Planet was issued and signed by many countries including India and China.

However, the United States and the United Kingdom did not sign this declaration due to concerns related to governance and regulatory approaches.

Memory Trick:

“Paris AI Summit: India co-chairs, US & UK don’t sign.”

→ Co-chairing and continuity → ✔

→ US/UK signing declaration → ❌

8.

GPS-Aided Geo Augmented Navigation (GAGAN) uses a system of ground stations to provide necessary augmentation. Which of the following statements is/are correct in respect of GAGAN?

I. It is designed to provide additional accuracy and integrity.

II. It will allow more uniform and high quality air traffic management.

III. It will provide benefits only in aviation but not in other modes of transportation.

Select the correct answer using the code given below.

(a) I, II and III

(b) II and III only

(c) I only

(d) I and II only

Correct Answer:

(d) I and II only

Explanation:

It was in easy question because of the statement 3 is easy to eliminate an statement one and two are very generic statement.

Statement I — Correct ✅

GAGAN is a Satellite Based Augmentation System (SBAS) developed by ISRO and Airports Authority of India to enhance accuracy, integrity, continuity, and availability of GPS signals, especially for civil aviation.

Statement II — Correct ✅

By providing uniform and precise navigation signals, GAGAN enables:

Better aircraft positioning

Improved approach and landing procedures

High-quality and harmonised air traffic management across Indian airspace.

Statement III — Incorrect ❌

GAGAN’s benefits are not limited to aviation.

It can also be used in:

Road and rail navigation

Maritime navigation

Disaster management

Surveying and mapping

Agriculture and fleet management

Hence, saying it benefits only aviation is incorrect.

Memory Trick:

“GAGAN = Accurate + Air + Also beyond aviation”

Accuracy & integrity ✅

Air traffic improvement ✅

Not aviation-only ❌

7.

Consider the following statements:

I. No virus can survive in ocean waters.

II. No virus can infect bacteria.

III. No virus can change the cellular transcriptional activity in host cells.

How many of the statements given above are correct?

(a) Only one

(b) Only two

(c) All the three

(d) None

Correct Answer:

(d) None

Explanation:

It was a easy question because of the extreme statements.

Statement I — Incorrect ❌

Viruses do survive in ocean waters.

Marine viruses are abundant and play a major role in marine ecosystems (e.g., regulating plankton populations).

Statement II — Incorrect ❌

Viruses can infect bacteria.

Such viruses are called bacteriophages (phages).

Statement III — Incorrect ❌

Viruses do change the cellular transcriptional activity of host cells.

They hijack the host’s transcription and translation machinery to produce viral components.

👉 Since all three statements are incorrect, none is correct.

One-line recall:

“Viruses live in oceans, infect bacteria, and hijack transcription.”

Expected Questions 

1️⃣ What is cellular transcriptional activity?

Transcription = making RNA from DNA.

Cellular transcriptional activity = which genes the cell is actively converting into RNA at a given time.

Normally, the cell transcribes its own genes for:

Metabolism

Growth

Repair

Normal functioning

2️⃣ What does “virus changes transcriptional activity” mean?

When a virus enters a host cell:

It redirects the cell’s transcription machinery.

Host genes are suppressed or ignored.

Viral genes are prioritised.

👉 In effect, the cell’s gene-expression program is rewritten.

3️⃣ How does a virus hijack transcription?

Depending on the virus type:

Viral genetic material (DNA or RNA):

Enters the nucleus (DNA viruses) or cytoplasm (RNA viruses).

Virus:

Uses host RNA polymerase (or brings its own enzymes).

Result:

Host machinery starts making viral mRNA instead of host mRNA.

👉 This is hijacking, not cooperation.

4️⃣ How does a virus hijack translation?

Translation = making proteins from mRNA.

Viral mRNA:

Binds to host ribosomes.

Ribosomes:

Produce viral proteins (capsid, enzymes, spikes).

Host protein production:

Is reduced or shut down.

👉 Ribosomes become virus factories.

5️⃣ Why is this essential for viruses?

Viruses:

Do not have ribosomes.

Cannot make proteins on their own.

Therefore, they must:

Exploit the host cell to survive and replicate.

6️⃣ Simple analogy (UPSC-safe)

Host cell = factory

Virus = hijacker

Hijacker:

Throws out factory’s original orders

Forces factory to produce only viral goods

7️⃣ One-line UPSC-ready statement

Viruses alter host cellular transcriptional activity by suppressing host gene expression and redirecting transcription and translation machinery exclusively towards viral replication.

Memory Trick:

“Virus doesn’t work — it reworks the cell.”

What is the meaning of making RNA from DNA?

Correct Answer:

Making RNA from DNA means copying genetic information stored in DNA into an RNA molecule so that the information can be used to make proteins. This process is called transcription.

Explanation:

1️⃣ Why is RNA made from DNA?

DNA stores genetic instructions permanently.

DNA does not directly make proteins.

The cell first makes a working copy of the required information in the form of RNA.

👉 RNA acts as a messenger between DNA and protein-making machinery.

2️⃣ What exactly happens in “making RNA from DNA”?

This process is called transcription.

A specific segment of DNA (a gene) is selected.

An enzyme called RNA polymerase:

Reads the DNA sequence.

Builds a complementary RNA strand.

The RNA produced is usually messenger RNA (mRNA).

👉 This mRNA carries the instructions to make a protein.

3️⃣ Simple flow (exam-oriented)

DNA → RNA → Protein

DNA → stores information

RNA → carries information

Protein → performs function

This is called the Central Dogma of Molecular Biology.

4️⃣ Simple analogy (for clarity)

DNA = Master blueprint in a library

RNA = Photocopy taken out of the library

Protein = Actual machine built using the photocopy

👉 DNA stays safe; RNA goes out to do the work.

5️⃣ Why transcription is important in viral infection?

Viruses force the host cell to:

Transcribe viral DNA/RNA, not host DNA.

Thus, viral RNA is made instead of host RNA.

6️⃣ UPSC-ready one-liner

Transcription is the process by which genetic information in DNA is copied into RNA for protein synthesis.

Memory Trick:

“DNA is Read, RNA is Written”

What is the difference between Gene, RNA, and DNA?

Correct Answer:

DNA is the molecule that stores genetic information; a gene is a specific functional segment of DNA; RNA is a working copy made from DNA that helps in protein synthesis.

Explanation:

1️⃣ DNA (Deoxyribonucleic Acid)

What it is: The master genetic material of the cell.

Role: Stores all genetic instructions of an organism.

Location: Mostly in the nucleus (in eukaryotes).

Nature: Long, double-stranded, stable molecule.

Function: Acts as the permanent blueprint.

👉 DNA = Library of instructions

2️⃣ Gene

What it is: A specific segment of DNA.

Role: Codes for:

A protein, or

A functional RNA.

Nature: Functional unit of heredity.

Relation to DNA:

Many genes together make up DNA.

👉 Gene = One meaningful instruction inside DNA

3️⃣ RNA (Ribonucleic Acid)

What it is: A copy made from DNA (by transcription).

Role: Helps express genetic information.

Nature: Single-stranded, short-lived.

Types (basic):

mRNA → carries message to make protein

tRNA → brings amino acids

rRNA → forms ribosomes

👉 RNA = Working copy used to build proteins

Key Differences (Conceptual):

DNA vs Gene

DNA is the entire book.

Gene is one chapter with instructions.

Gene vs RNA

Gene is a part of DNA.

RNA is a copy made from a gene.

DNA vs RNA

DNA stores information.

RNA uses information.

UPSC-ready one-liners:

DNA stores genetic information.

Gene is a functional segment of DNA.

RNA is the intermediate that helps convert genetic information into proteins.

Memory Trick:

“DNA stores, Gene specifies, RNA executes”

Who makes protein? And what is amino acids and ribosomes?

Correct Answer:

Proteins are made by ribosomes; amino acids are the building blocks of proteins; ribosomes are cellular structures that assemble amino acids into proteins using instructions from RNA.

Explanation:

1️⃣ Who makes proteins?

Ribosomes make proteins.

They read the instructions carried by messenger RNA (mRNA).

Using these instructions, ribosomes assemble proteins step by step.

👉 Protein-making = translation, and ribosome is the site.

2️⃣ What are amino acids?

Amino acids are small organic molecules.

They are the basic building blocks of proteins.

Proteins are long chains (polymers) made by linking amino acids together.

Key points:

About 20 standard amino acids are commonly used.

Different sequences and combinations of amino acids → different proteins.

Example roles of proteins:

Enzymes

Hormones

Antibodies

Structural proteins (muscle, skin)

👉 Amino acids = letters; Protein = word/sentence.

3️⃣ What are ribosomes?

Ribosomes are non-membrane-bound cellular organelles.

They are made of ribosomal RNA (rRNA) and proteins.

Function:

Bind to mRNA,

Read its code,

Join amino acids in the correct order.

Location:

Free in cytoplasm, or

Attached to rough endoplasmic reticulum (RER).

👉 Ribosome = protein factory.

4️⃣ How all three work together (flow you must remember)

DNA → instructions

RNA (mRNA) → carries instructions

Ribosome → reads instructions

Amino acids → assembled into protein

Flow:

DNA → RNA → Protein

5️⃣ UPSC-ready one-liners

Ribosomes are the sites of protein synthesis.

Amino acids are the monomers of proteins.

Proteins are produced by translating mRNA on ribosomes.

Memory Trick:

“Ribo Reads, Amino Adds”

Ribosome reads the code

Amino acids add up to form protein

What is the meaning of polymers?

Correct Answer:

Polymers are large molecules made by joining many small, repeating units called monomers.

Explanation:

Word origin:

Poly = many

Mer = unit

→ Polymer = many units joined together

Basic idea:

A polymer is a long chain molecule.

It is formed when many monomers chemically bond in a repeating pattern.

Simple structure logic:

Monomer + Monomer + Monomer + … → Polymer

Why polymers matter (biology & chemistry):

Many important biological molecules are polymers.

Their properties depend on the type and sequence of monomers.

Examples (UPSC-relevant):

Proteins → Polymers of amino acids

DNA / RNA → Polymers of nucleotides

Carbohydrates (starch, cellulose) → Polymers of glucose

Plastics (polythene) → Polymers of ethylene

Polymer vs Monomer (clear distinction):

Monomer → single small unit

Polymer → many monomers joined together

Simple analogy (exam-safe):

Brick = Monomer

Wall = Polymer

Memory Trick:

“Many mers make a polymer”

→ One unit = monomer

→ Many units = polymer

6.

With reference to monoclonal antibodies, often mentioned in news, consider the following statements:

I. They are man-made proteins.

II. They stimulate immunological function due to their ability to bind to specific antigens.

III. They are used in treating viral infections like that of Nipah virus.

Which of the statements given above are correct?

(a) I and II only

(b) II and III only

(c) I and III only

(d) I, II and III

Correct Answer:

(d) I, II and III

Explanation:

Statement I — Correct ✅

Monoclonal antibodies are laboratory-made (man-made) proteins.

They are engineered to mimic natural antibodies produced by the immune system.

Statement II — Correct ✅

Monoclonal antibodies bind to specific antigens (high specificity).

By binding, they:

Neutralise pathogens, or

Mark them for destruction by immune cells.

Thus, they stimulate or modulate immune function.

Statement III — Correct ✅

Monoclonal antibodies have been used in the treatment of viral infections, including Nipah virus (e.g., experimental monoclonal antibody therapies like m102.4).

They are also used against viruses such as Ebola and COVID-19.

👉 Hence, all three statements are correct.

Memory Trick:

“Mono = Made, Match, Medicine”

Made in lab → man-made proteins

Match one antigen → high specificity

Medicine for viruses → including Nipah

Expected question 

What is the meaning of antibodies and antigens? What is the difference between them?

Correct Answer:

An antigen is a foreign substance that triggers an immune response, while an antibody is a specific protein produced by the immune system to recognise and bind to that antigen.

Explanation:

1️⃣ Meaning of Antigen

An antigen is any foreign substance that the body identifies as non-self.

It initiates (triggers) an immune response.

Key points:

Usually a protein or polysaccharide on pathogens.

Found on viruses, bacteria, toxins, pollen, etc.

Has specific parts called epitopes that are recognised by the immune system.

Examples:

Viral spike protein

Bacterial toxin

Pollen allergen

👉 Antigen = Trigger

2️⃣ Meaning of Antibody

An antibody is a protein made by B-lymphocytes (B-cells).

It is produced in response to an antigen.

It binds specifically to that antigen.

Key points:

Highly specific (lock-and-key fit).

Binding can:

Neutralise the antigen, or

Mark it for destruction by immune cells.

Examples:

Antibodies formed after vaccination

Therapeutic monoclonal antibodies

👉 Antibody = Defender

3️⃣ Difference between Antigen and Antibody (Conceptual)

Nature:

Antigen → Foreign substance

Antibody → Immune protein

Role:

Antigen → Causes immune response

Antibody → Responds to antigen

Origin:

Antigen → Comes from outside (or abnormal self)

Antibody → Produced inside the body

Function:

Antigen → Stimulus

Antibody → Protection

4️⃣ Simple example (for clarity)

Virus enters the body → viral protein = antigen.

Body produces a matching antibody.

Antibody binds the antigen → virus neutralised.

5️⃣ UPSC-ready one-liner

Antigens induce immunity; antibodies execute immunity.

Memory Trick:

“GEN causes, BODY blocks”

AntiGEN → Generates immune response

AntiBODY → Body’s weapon to block it

What is the meaning of autoimmune disease and diagnostics?

Correct Answer:

An autoimmune disease is a condition in which the body’s immune system mistakenly attacks its own healthy cells; diagnostics refers to the methods and tests used to detect, identify, and confirm diseases.

Explanation:

1️⃣ Meaning of Autoimmune Disease

Autoimmune = Auto (self) + immune (defence).

In an autoimmune disease:

The immune system fails to recognise “self”, and

Produces antibodies or immune cells against the body’s own tissues.

What goes wrong (conceptually):

Normal: Immune system attacks foreign antigens.

Autoimmune: Immune system attacks self-antigens.

Examples (UPSC-relevant):

Rheumatoid arthritis → attacks joints

Type 1 diabetes → attacks insulin-producing pancreatic cells

Systemic lupus erythematosus (SLE) → attacks multiple organs

Multiple sclerosis → attacks nerve coverings

👉 Key idea: Defence system turns destructive against self.

2️⃣ Meaning of Diagnostics

Diagnostics means the process of identifying a disease.

It includes:

Detecting whether a disease is present,

Determining its type, cause, or stage.

What diagnostics involve:

Laboratory tests (blood, urine, antibodies)

Imaging (X-ray, MRI, CT)

Molecular tests (PCR, antigen/antibody tests)

Clinical examination

👉 Diagnostics answers: “What disease is it?”

3️⃣ Diagnostics in Autoimmune Diseases (Linkage)

Autoimmune diseases are diagnosed by detecting:

Autoantibodies (e.g., ANA in lupus),

Inflammatory markers, and

Organ-specific damage.

👉 Without diagnostics, autoimmune diseases are often misdiagnosed, because symptoms mimic other illnesses.

4️⃣ UPSC-ready One-line Definitions

Autoimmune disease: A disorder in which the immune system attacks the body’s own cells and tissues.

Diagnostics: Scientific methods and tests used to detect and confirm diseases.

Memory Trick:

“Auto = Self attack, Diagnostics = Disease detection”

What is the meaning of B-lymphocytes, B-cells?

Correct Answer:

B-lymphocytes (B-cells) are a type of white blood cell that produce antibodies and provide humoral (antibody-mediated) immunity.

Explanation:

1️⃣ What are B-lymphocytes?

B-lymphocytes, commonly called B-cells, are immune cells.

They are part of the adaptive immune system.

Their main job is to make antibodies against specific antigens.

👉 B = Bone marrow (where they mature).

2️⃣ What exactly do B-cells do?

When an antigen enters the body:

A specific B-cell recognises the antigen.

That B-cell becomes activated and multiplies (clonal expansion).

It differentiates into:

Plasma cells → produce large amounts of antibodies

Memory B-cells → provide long-term immunity

3️⃣ Why are B-cells important?

They provide specific, targeted defence.

They are the source of antibodies, including:

Natural antibodies (after infection)

Vaccine-induced antibodies

Monoclonal antibodies (lab-made versions)

4️⃣ B-cells vs T-cells (for clarity)

B-cells → make antibodies (humoral immunity)

T-cells → kill infected cells / coordinate immunity (cell-mediated immunity)

5️⃣ UPSC-ready one-liner

B-lymphocytes are antibody-producing white blood cells that recognise antigens and mediate humoral immunity.

Memory Trick:

“B-cell = Body’s Antibody Factory”

What is the meaning of Monoclonal Antibodies?

Correct Answer:

Monoclonal antibodies are identical, laboratory-made antibodies produced from a single clone of immune cells, designed to bind to one specific antigen.

Explanation:

“Mono” = one

→ They come from one single clone of cells.

“Clonal” = identical copies

→ All antibodies are exactly the same in structure and function.

What they do:

Bind to one specific antigen (lock-and-key specificity).

Can neutralise pathogens, block receptors, or mark targets for immune destruction.

Why they are special:

Highly specific (unlike polyclonal antibodies, which bind multiple antigens).

Predictable and targeted action, useful in medicine.

How they are made (conceptual):

A single antibody-producing cell is selected and cloned in the lab.

Large quantities of identical antibodies are produced.

Uses (UPSC-relevant):

Treatment of viral infections (e.g., Nipah, Ebola, COVID-19)

Cancer therapy (targeting tumour antigens)

Autoimmune diseases and diagnostics

Memory Trick:

“Mono = One target, One type”

→ One clone → One antibody → One antigen

5.

Consider the following statements:

I. It is expected that Majorana 1 chip will enable quantum computing.

II. Majorana 1 chip has been introduced by Amazon Web Services (AWS).

III. Deep learning is a subset of machine learning.

Which of the statements given above are correct?

(a) I and II only

(b) II and III only

(c) I and III only

(d) I, II and III

Correct Answer:

(c) I and III only

Explanation:

Statement I — Correct ✅

The Majorana 1 chip is designed around Majorana fermions, which are expected to enable topological quantum computing.

Such chips aim to create more stable (fault-tolerant) qubits, a key requirement for practical quantum computing.

Statement II — Incorrect ❌

The Majorana 1 chip was introduced by Microsoft, not by Amazon Web Services (AWS).

AWS is active in quantum computing (e.g., Amazon Braket), but it did not introduce the Majorana chip.

Statement III — Correct ✅

Deep learning is a subset of machine learning, which itself is a subset of artificial intelligence (AI).

Deep learning uses multi-layered neural networks.

4.

What is the common characteristic of the chemical substances generally known as CL-20, HMX and LLM-105, which are sometimes talked about in media?

(a) These are alternatives to hydrofluorocarbon refrigerants

(b) These are explosives in military weapons

(c) These are high-energy fuels for cruise missiles

(d) These are fuels for rocket propulsion

Correct Answer:

(b) These are explosives in military weapons

Explanation:

CL-20:

A high-energy explosive (hexanitrohexaazaisowurtzitane).

Used in advanced military explosives due to very high detonation velocity.

HMX:

A powerful secondary explosive (cyclotetramethylene-tetranitramine).

Widely used in military warheads, detonators, and plastic explosives.

LLM-105:

A low-sensitivity high explosive.

Designed to provide high explosive performance with greater safety, used in modern military applications.

These substances are:

Explosives, not refrigerants.

Not fuels (they detonate; fuels burn progressively).

Used for detonation, not propulsion.

👉 Hence, the correct common characteristic is that all are military explosives.

Memory Trick:

“CL–HMX–LLM = BOOM materials”

→ High-energy explosives, not fuels or refrigerants.

3.

In the context of electric vehicle batteries, consider the following elements:

I. Cobalt

II. Graphite

III. Lithium

IV. Nickel

How many of the above usually make up battery cathodes?

(a) Only one

(b) Only two

(c) Only three

(d) All the four

Correct Answer:

(c) Only three

Explanation:

Cobalt — Correct ✅

Used in lithium-ion battery cathodes (e.g., LCO, NMC chemistries).

Graphite — Incorrect ❌

Graphite is used in the anode, not the cathode.

Lithium — Correct ✅

Lithium is a core constituent of the cathode material in all lithium-ion batteries.

Nickel — Correct ✅

Widely used in high-energy-density cathodes (e.g., NMC, NCA batteries).

👉 Therefore, Cobalt, Lithium, and Nickel usually make up battery cathodes, while Graphite does not.

2.

With reference to Unmanned Aerial Vehicles (UAVs), consider the following statements:

I. All types of UAVs can do vertical landing.

II. All types of UAVs can do automated hovering.

III. All types of UAVs can use battery only as a source of power supply.

How many of the statements given above are correct?

(a) Only one

(b) Only two

(c) All the three

(d) None

Correct Answer:

(d) None

Explanation:

It was an easy question because all the three statements are extreme statement and UPSC usually use extreme words[ all, none] for wrong statement.

Statement I — Incorrect ❌

Fixed-wing UAVs require a runway or launcher for take-off and landing.

Only rotary-wing and some VTOL (Vertical Take-Off and Landing) UAVs can land vertically.

Hence, not all UAVs can do vertical landing.

Statement II — Incorrect ❌

Hovering is possible only for rotary-wing UAVs (e.g., quadcopters, helicopters).

Fixed-wing UAVs must maintain forward motion to stay airborne and cannot hover, automated or otherwise.

Statement III — Incorrect ❌

UAVs can be powered by multiple sources, such as:

Batteries

Internal combustion engines (petrol/diesel)

Hybrid systems

Solar power

Hydrogen fuel cells

Therefore, battery-only power is not universal.

👉 Thus, none of the statements is correct.

1.

Consider the following types of vehicles:

I. Full battery electric vehicles

II. Hydrogen fuel cell vehicles

III. Fuel cell-electric hybrid vehicles

How many of the above are considered as alternative powertrain vehicles?

(a) Only one

(b) Only two

(c) All the three

(d) None

Correct Answer:

(c) All the three

Explanation:

Alternative powertrain vehicles are those that do not rely on conventional internal combustion engines (petrol/diesel) for propulsion.

Powertrain is the system that generate and deliver power to move vehicle.

Statement I — Correct ✅

Full battery electric vehicles (BEVs) use electric motors powered by onboard batteries.

→ No internal combustion engine involved.

Statement II — Correct ✅

Hydrogen fuel cell vehicles (FCEVs) generate electricity onboard using hydrogen fuel cells to power electric motors.

→ Alternative to fossil-fuel engines.

Statement III — Correct ✅

Fuel cell-electric hybrid vehicles combine:

Fuel cell system, and

Electric battery system,

both driving electric propulsion.

→ Clearly an alternative powertrain.

👉 Therefore, all three fall under alternative powertrain vehicles.

Memory Trick:

“If engine is not petrol–diesel, it’s alternative”

Battery ✔

Hydrogen ✔

Fuel cell + electric ✔