Polymer Electrolyte Membrane Fuel Cells
• PEMFC convert the chemical energy stored in
hydrogen fuel directly and efficiently to electrical
energy with water as the only byproduct without
the need for grid power as required by conventional
battery backup systems.
Hence, statements 1 and 2 are correct.
• Potential: To reduce energy use, pollutant emissions
and dependence on fossil fuels and providing
sustainable electricity.
• Advantage: Operational capability at low temperatures
with applications in decentralised power generation systems.
Hence, statement 3 is correct.

Pressurized Heavy Water Reactor
• PHWR is a nuclear power reactor, commonly using
unenriched natural uranium as its fuel. It uses
heavy water (Deuterium oxide D2O) as its coolant
and moderator.
Hence, statement 1 is correct.
• While heavy water is significantly more expensive
than ordinary light water, it yields a greatly enhanced
neutron economy, allowing the reactor to operate
without fuel enrichment facilities.

Light Water Reactor
• The light water reactor is a type of thermal – neutron
reactor that utilizes normal water as opposed to
heavy water.
• It is fuelled by Low Enriched Uranium.
Hence, statement 2 is correct.
• It uses water as both a coolant method and a neutron
moderator.
• It produces heat by controlled nuclear fission.

Prototype Fast Breeder Reactor
• A breeder reactor is a nuclear reactor that generates
more fissile material than it consumes. These are
designed to extend the nuclear fuel supply for electric
power generation.
• Breeder reactors achieve this because their neutron
economy is high enough to create more fissile fuel
than they use, by irradiation of a fertile material,
such as uranium-238 or thorium-232 that is loaded
into the reactor along with fissile fuel.
• PFBR is a 500 MWe fast breeder nuclear reactor
presently being constructed at the Madras Atomic
Power Station in Kalpakkam (Tamil Nadu). It is fuelled
by Mixed Oxide (MOX) Fuel.
Hence, statement 3 is correct.

Key Points
• The current study confirms an earlier Chinese study
and also suggests the probable time of divergence
of the two viruses.
– Based on the nearly 96% genome sequence
identity between SARS-CoV-2 and RaTG13, it was
held that an origin in bats is probable for the
Covid-19 outbreak.
• RaTG13 and SARS-CoV-2 share a single ancestral
lineage and estimate that SARS-CoV-2 genetically
diverged from related bat sarbecoviruses in 1948,
1969 and 1982.
– The ability of the spike protein in the virus to bind
to Angiotensin-Converting Enzyme 2 (ACE2)
human receptors is an ancestral train within bats.

Angiotensin-Converting Enzyme 2 (ACE2)
• ACE2 is a protein on the surface of many cell types.
Hence, statement 1 is correct.
• It is an enzyme that cuts the larger protein
angiotensinogen for regulation of functions in the cell.
• ACE2 acts as a cellular doorway – a receptor – for
the SARS-CoV-2 virus.
• The SARS-CoV-2 virus binds to ACE2, using the spikelike
protein on its surface, like a key being inserted into a lock –
prior to entry and infection of cells.
Hence, statement 2 is correct.

Key Points
• The vaccine has been called Sputnik V, named after
the first artificial Earth satellite, Sputnik-I launched
by the Soviet Union.
• It is the first Covid-19 vaccine to be approved.
– However, a Chinese vaccine had been cleared for
‘limited use’ before this. It is an adenovirus vector
vaccine approved to be administered only on
soldiers of the People’s Liberation Army.

Cataract:
• It is a major form of blindness that occurs when
the structure of crystallin proteins that make up
the lens in human eyes deteriorates.
Hence, sattement 2 is correct.
• Such deterioration causes damaged or disorganised
proteins to aggregate and forms a milky blue or
brown layer, which ultimately affects lens
transparency.
• As with ageing and under various conditions, the
lens protein crystallin aggregates to form opaque
structures in the eye lens, which impairs vision
and causes cataract.
Hence, sattement 1 is correct.

Universal Immunization Programme
• It was launched by the government in 1985, to prevent mortality and morbidity in children and pregnant women against 12 vaccine-preventable diseases.
• Under UIP free of cost vaccination is provided against twelve vaccine-preventable diseases i.e. Tuberculosis,
Diphtheria, Pertussis, Tetanus, Polio, Hepatitis B, Pneumonia , Meningitis due to Haemophilus Influenzae type b (Hib), Measles, Rubella, Japanese Encephalitis (JE) and Rotavirus diarrhoea.
• The programme is one of the largest health programmes in the world. Despite being operational for many years, UIP has been able to fully immunize only 65% of children under 1 year of age.

Key Differences Between Concave and Convex lens
1. The key factor of differentiation between a concave and a convex lens is that a concave lens diverges the light rays that travel parallel to its principal axis. As against a convex lens, converges the light rays that incident on it along the direction of its principal axis.
Due to the nature of the lens, the incident light rays either converges or diverges after passing through it. Thus, the concave lens is also known as a diverging lens while the convex lens is known as a converging lens.
2. These two lenses are also differentiated on the basis of shape possessed by them. A concave lens exhibits a cave-like structure from the outside as it has a thinner middle portion and thick edges. However, in the convex lens, the edges are comparatively thinner than the center of the lens.
3. The polarity of the focal length is negative in the case of the concave lens while it is positive for a convex lens. Due to this the diverging lens sometimes referred as a negative lens while the converging one is referred as a positive lens.
Hence, statement 1 is incorrect.
4. The image from a concave lens is always virtual and erect. While the real and inverted image is formed from a convex lens. However, in case the object is very near to the lens then the resultant image is virtual, erect, and magnified.
Hence, statement 2 is correct.
5. Lenses are used for the correction of issues related to vision. The concave lenses are used to cure myopia while the convex lens corrects hypermetropia.
Hence, statement 3 is incorrect.
6. Convex lenses hold magnifying abilities thus are generally used in the lens of microscope and telescope, also, the human eye lens is concave in nature. But, a convex lens is used in lasers, flashlights of vehicles as well as peepholes of doors.
7. In the case of a concave lens, the body or object near it appears to be present at distant and is smaller than the actual one. However, when a body is present in front of a convex lens then it appears in a way that it is present nearer and is of larger dimensions than the original body.

Key Points
• SFTS is caused by the Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV) which belongs to the Bunyavirus family and is transmitted to humans through tick bites. Hence, statement 1 is not correct.
– A tick called Asian Longhorned Tick (Haemaphysalis longicornis) is believed to be the primary vector (carrier) of the virus. Hence, statement 3 is correct.
• The virus is often transmitted to humans from animals like goats, cattle, deer and sheep and regular contact with these animals makes farmers, hunters and pet owners vulnerable to the disease.
• Despite being infected by the virus, animals generally do not show any symptoms associated with SFTSV.
• Its incubation period is anywhere between 7 and 13 days.

Key Points
• The Bharat Air Fibre services are being introduced
by Bharat Sanchar Nigam Limited (BSNL) as a part
of the Digital India initiative by the Government of
India. It is being scaled pan-India.
• Aim: To provide BSNL fibre-to-the-home (FTTH)
wireless connectivity up to a range of 20 km from
the BSNL points of presence.
• The connectivity speed is 100 Mbps and BSNL is
offering various broadband plans in wireline and
wireless segments.

Oncomirs:
• The miRNAs associated with cancer are called
Oncomirs.
• They affect cancer growth through inhibiting or
enhancing the functions of certain proteins.
• Oncomirs affect cancer by suppressing the
performance of tumour-suppressing agents which
can prevent the growth and spread of cancer cells
and sometimes prevent tumour growth itself.

Ribonucleic Acid
• RNA is a polymer of ribonucleotides and an important biological macromolecule that is present
in all biological cells. Hence, statement 3 is correct.
• It is principally involved in the synthesis of proteins, carrying the messenger instructions from Deoxyribonucleic acid (DNA), which itself contains the genetic instructions required for the development and maintenance of life. Hence, statement 1 is correct.
• RNA differs from DNA in three basic respects:
– RNA employs uracil as a nitrogenous base, in place of the thymine used in DNA.
– RNA nucleotides possess a hydroxyl group at the 2nd position, while DNA is deoxygenated at that position to a proton.
– RNA is more often found single-stranded than DNA, which is typically completely base-paired into a double helix. Hence, statement 2 is correct.

Near-Earth Objects (NEOs):
• NEOs are comets and asteroids pushed by the
gravitational attraction of nearby planets into
orbits which allow them to enter the Earth’s
neighbourhood.
• These objects are composed mostly of water ice
with embedded dust particles.
Hence, statement 1 is correct.
• NEOs occasionally approach close to the Earth as
they orbit the Sun and have a fixed path trajectory.
Hence, statement 2 is incorrect.
• NASA’s Center for Near-Earth Object Study
(CNEOS) determines the times and distances of
these objects, when their approach to the Earth is
close, through the Asteroid Watch Widget.

Asteroids
• Asteroids orbit the Sun and are small bodies in the
solar system.
Hence, statement 3 is correct.
• They are made up of metals and rocks.
• They tend to have shorter and elliptical orbits.
• They do not produce a coma or tail atmosphere.
• The asteroid belt is a torus-shaped region in the
Solar System, located roughly between the orbits
of the planets Jupiter and Mars.
Hence, statement 4 is correct.

Comet
• Comets also orbit the Sun and are relatively small
bodies of the solar system.
Hence, statement 3 is correct.
• They are made up of ice and hydrocarbons.
Hence, statement 1 is not correct.
• Comets have an eccentric orbit.
Hence, statement 2 is not correct.
• When comets approach the sun, some part of their
ice melts and the other materials vapourise due to
the heat of the sun. This results in a glowing halo
that extends outwards through space.
-Therefore, a thin atmospheric tail is formed
when close to the Sun.

Protozoa
• These are the single-celled eukaryotes, either freeliving
or parasitic, which feed on organic matter such
as other microorganisms or organic tissues and debris.
Hence, staement 1 is correct.
– Eukaryotes are organisms whose cells have a
nucleus enclosed within membranes, unlike
prokaryotes, which have no membrane-bound
organelles.
– A parasite is an organism that lives on or in a
host and gets its food from or at the expense
of its host. For example, plasmodium parasites
which cause malaria.
• Habitat: Mostly they are aerobic (with oxygen) but
some are anaerobic (without oxygen) and present
in the rumen or human intestine.
Hence, staement 2 is correct.
• Size and Shape: The size and shape of Protozoa vary
greatly, from microbial (1µm) to large enough and
can be seen by the naked eye.
• Nutrition: Protozoans are heterotrophs and have
holozoic nutrition.
Hence, staement 3 is correct.
– Holozoic nutrition can be defined as a method of
nutrition which involves the ingestion of some
complex organic substances (such as parts of
a plant or animal) that may be in the solid or
the liquid form.

Amoebiasis
• It is a disease caused by the parasite Entamoeba
histolytica.
Hence, statement 1 is correct.
• Amoebiasis infection is most common in tropical
areas with untreated water. E.g. India .
Hence, statement 2 is correct.
• It spreads through drinking or eating uncooked
food, such as fruit, that may have been washed in
contaminated local water.
Hence, statement 3 is correct.
• If symptoms occur, they may be mild and include
cramping and diarrhoea.
• It can be treated through antibiotics.
Hence, statement 4 is incorrect.

Tamar Valley
• Tamar valley is located in the south of England and
is a rich archaeological landscape with many sites
belonging to the Iron Age and Roman era.
Hence, statement 1 is correct.
• The area is a World Heritage Site due to its historic
mining activities.
Hence, statement 2 is correct.
• A World Heritage Site is a place that is listed by
the United Nations Educational, Scientific and
Cultural Organization (UNESCO) for its special
cultural or physical significance.
• The list of World Heritage Sites is maintained by
the international ‘World Heritage Programme’,
administered by the UNESCO World Heritage
Committee.

LiDAR
• Description:
– LiDAR (Light Detection and Ranging) is a remote sensing method that uses light in the form of a pulsed
laser to measure ranges and variable distances.
– These light pulses, combined with other data recorded by the airborne system, generate precise, three-dimensional information about the shape of the Earth and its surface characteristics.
– A LiDAR instrument principally consists of a laser, a scanner and a specialized GPS receiver.
– Airplanes and helicopters are the most commonly used platforms for acquiring LiDAR data over broad areas.
• Applications:
– LiDAR is used for agriculture, hydrology and water management systems.
– Geology-related applications.
– It is also used in archaeology.

RT-nPCR Test:
• It does not depend on RT-qPCR (testing approved
by the ICMR) but uses standard RT-PCR as part
of an endpoint assay (i.e. to measure biochemical
activity of a sample).
• It has been developed on a low-cost and low-tech
model.
Hence, statement 3 is correct.
• This new test is awaiting approval from the Indian
Council of Medical Research (ICMR).

RT-qPCR Test:
• The ICMR has recommended only Reverse Transcription
Polymerase Chain Reaction (RT-qPCR) test for novel
coronavirus testing.
Hence, statement 1 is not correct.
• PCR is an enzymatic reaction used to amplify
DeoxyRibonucleic Acid (DNA).
• Unlike conventional PCR, which relies on end
point analysis, qPCR enables the analyst to
monitor DNA amplification in real time, as the
reaction proceeds. This allows quantification
of DNA.
Hence, statement 2 is correct.
• However, coronavirus is made up of Ribonucleic
Acid (RNA). Therefore to detect coronavirus,
RNA is converted into DNA using a technique
called Reverse Transcription (RT).

Compulsory Licensing
• It allows governments to license third parties (that
is, parties other than the patent holders) to produce
and market a patented product or process without
the consent of patent owners.
Hence, statement 1 is correct.
• Any time after three years from date of sealing of
a patent, application for compulsory license can
be made, provided:
– Reasonable requirements of the public have not
been satisfied.
– Patented inventions are not available to the
public at a reasonably affordable price.
– Patented inventions are not carried out in India.
• It is regulated under the Indian Patent Act, 1970.
Hence, statement 2 is correct.
• The Trade Related Aspects of Intellectual Property
Rights (TRIPS) Agreement does not specifically list
the reasons that might be used to justify compulsory
licensing.
Hence, statement 3 is incorrect.
• However, the Doha Declaration on TRIPS and Public
Health confirms that countries are free to determine
the grounds for granting compulsory licences, and to
determine what constitutes a national emergency.