Science-Tech, Environment & Geography MCQs for Prelims – 28th May 2025

Welcome to today’s curated set of MCQs from the Science & Technology, Environment, and Geography segments, specially aligned with the evolving trend of the UPSC Civil Services Preliminary Examination. These questions are not just a quiz, but a resource designed to familiarize you with the exact nature of questions asked in Prelims — where static concepts are tested through a current affairs lens.

Each question below is framed using recent developments in the news and backed by clear, concise explanations to help you link dynamic events with foundational knowledge. Topics covered today include: Polar Satellite Launch Vehicle (PSLV), HeLa Cells and Nobel Prize Connections, Hoyle–Narlikar Theory of Gravity, Life Cycle of Stars, JN.1 COVID Variant, Shirui Lily Festival and Biodiversity, Morphological Ridge in Delhi, 2025 Lion Census in India and more...

Use this as a daily revision tool to refine your understanding, build context, and learn how UPSC frames conceptual questions from contemporary issues.

QUESTION 1

With reference to the Hoyle–Narlikar theory of gravity, consider the following statements:

1. The theory incorporates Mach’s principle, which suggests that the mass of every object is influenced by its interaction with all other masses in the universe.
2. Einstein successfully integrated Mach’s principle into his General Theory of Relativity.
3. The theory proposed a “creation field” (C-field)—a hypothetical negative-energy field responsible for the continuous creation of matter.

Which of the statements given above is/are correct?

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

Answer: (a)

Explanation

• Jayant Narlikar, a distinguished Indian astrophysicist and recipient of the Padma Vibhushan, passed away at the age of 87. He is most well-known for his work on the Hoyle–Narlikar theory of gravity, developed in collaboration with British astronomer Fred Hoyle in 1964.
• This theory aimed to offer an alternative framework to Einstein’s General Theory of Relativity. A key concept in this theory is Mach’s Principle, which posits that an object’s inertial mass arises from its interaction with the rest of the universe. Hence, statement 1 is correct.
• Although Einstein was deeply influenced by Mach’s Principle, he was ultimately unsuccessful in formally incorporating it into his general relativity framework. Therefore, statement 2 is incorrect.
• The theory introduced a novel concept known as the "creation field" or C-field, which represents a negative-energy field postulated to allow the continuous creation of matter. This concept supports the steady-state model of the universe, proposing an eternal, unchanging cosmos with no origin point. Thus, statement 3 is correct.
• However, the Hoyle–Narlikar theory lost prominence after the discovery of the cosmic microwave background (CMB) radiation in 1965, which provided strong evidence in favor of the Big Bang theory, contradicting the steady-state model.

QUESTION 2

Which of the following missions undertaken by the Polar Satellite Launch Vehicle (PSLV) were unsuccessful?

1. EOS-07 mission

2. The very first PSLV launch in 1993

3. C-39 mission

Select the correct answer using the codes given below:

(a) 1 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 3 only

Ans B

Explanation

• The Polar Satellite Launch Vehicle (PSLV), developed by the Indian Space Research Organisation (ISRO), has been a cornerstone of India's space program. Over the years, it has earned a reputation as a highly reliable launch vehicle.
• However, in its long operational history, PSLV has encountered two mission failures:

• The first failure occurred during its maiden flight in 1993, which did not succeed due to control system malfunctions.
• The second failure was the PSLV-C39 mission in 2017, when the heat shield failed to separate, trapping the satellite inside and rendering the mission unsuccessful.

• The EOS-07 mission, launched aboard the PSLV-C53 rocket in 2023, was successful and therefore not part of the failed missions. Hence, Statement 1 is incorrect, while Statements 2 and 3 are correct.
• As of now, out of more than 60 PSLV launches, only two have failed, underlining the vehicle’s high success rate and its importance to India’s satellite deployment strategy.

Must Read: PSLV-C61 Mission and the EOS-09 Satellite

QUESTION 3

With reference to stars and their life cycles, consider the following statements:

1. All stars, regardless of how long they exist, sustain themselves through a balance between inward gravitational pull and outward pressure from nuclear reactions.
2. In a star's core, hydrogen nuclei undergo fusion to form helium.
3. Once a star exhausts its fuel supply, gravity dominates — and the manner in which the star dies is determined solely by its mass.

How many of the statements given above are correct?

(a) Only one
(b) Only two
(c) All three
(d) None

Answer: (c)

Explanation

• While stars may appear to shine indefinitely, they too follow a life cycle dictated by mass and internal processes. Some stars endure for billions of years, while others have much shorter lifespans.
• A star maintains its structure by balancing two opposing forces — gravity, which pulls matter inward, and the pressure from nuclear fusion, which pushes outward. This equilibrium allows the star to shine steadily during its main sequence phase. Hence, Statement 1 is correct:
• Deep within a star’s core, conditions of extremely high pressure and temperature enable nuclear fusion, where hydrogen atoms are fused into helium, releasing a tremendous amount of energy. This energy radiates outward and provides the pressure needed to counter gravity. Hence, Statement 2 is correct
• This mechanism of stellar fusion was not understood until 1938, when Hans Bethe, a German-American physicist, formulated the nuclear reactions involved — work that earned him the Nobel Prize in Physics.
• Eventually, a star's nuclear fuel runs out. At this stage, gravity becomes dominant. What follows depends on the star’s mass: smaller stars may become white dwarfs, while more massive ones may end as neutron stars or even black holes. Hence, Statement 3 is correct:

QUESTION 4

Consider the following statements about HeLa cells:

1. They were the first successfully cloned human cells.

2. These cells helped identify Bovine Papillomavirus (BPV) as a major cause of cervical cancer.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Ans A

Explanation

• The HeLa cell line holds a foundational place in biomedical research and is widely regarded as one of the most significant tools in cell biology and medicine.
• HeLa cells, derived from the cervical cancer tissue of Henrietta Lacks in 1951, were the first human cells to be successfully cloned and grown continuously in culture. They played a crucial role in developing the polio vaccine, as used by Jonas Salk during his vaccine trials. Hence, Statement 1 is correct
• HeLa cells were instrumental in the discovery that Human Papillomavirus (HPV)—not Bovine Papillomavirus (BPV)—is the primary viral agent linked to cervical cancer. This breakthrough led to the creation of the HPV vaccine, and Harald zur Hausen received the Nobel Prize in Physiology or Medicine in 2008 for his work in this area. Hence, Statement 2 is incorrect

QUESTION 5

With reference to the JN.1 variant of COVID, consider the following statements:

1. It is a sub-lineage of the Omicron variant.

2. This variant is distinguished by its heightened transmissibility and potential to evade immune responses, even in the vaccinated population.

3. This variant poses the greatest risk to older adults and people with existing health conditions.

Which of the statements given above are correct?

(a) 1 and 2 only

(b) 2 and 3 only

(c) 1 and 3 only

(d) 1, 2 and 3

Ans D

Explanation

• The JN.1 strain is a sub-lineage of the Omicron variant, which has already given rise to several other mutations over time. Although not a brand-new variant, JN.1 has drawn attention for its distinct properties. Hence, Statement 1 is correct.
• Medical experts, including Dr. Harish Chafle, have noted that JN.1 exhibits significantly higher transmissibility and a greater ability to evade immune defenses, even among individuals who have been vaccinated. This trait raises concerns regarding the effectiveness of existing immunity in preventing infections. Hence, Statement 2 is correct.
• In terms of health impact, JN.1 is considered more threatening to immunocompromised individuals, including senior citizens and people suffering from chronic conditions such as diabetes, respiratory illnesses, or cardiovascular diseases. While children and healthy adults may also be infected, they typically experience mild symptoms and recover quickly. Hence, Statement 3 is correct.

QUESTION 6

The Shirui Lily Festival is one of the major tourism festivals organised by:

(a) Arunachal Pradesh

(b) Sikkim

(c) Kerala

(d) Manipur

Ans D

Explanation

— Imphalgram, a popular Instagram handle headquartered in Imphal, posted a video of a “road trip” to the hill station of Ukhrul, which is around 80 miles away. The film depicts the creators going to Ukhrul via gorgeous hill roads, passing by markets and security officers and cars that have become common in the state during the last two years.

— They visit various locations during the Shirui Lily Festival, one of two major tourism events conducted by the Manipur government.

— The Shirui Lily Festival takes place in Ukhrul town and Shirui hamlet in Ukhrul district, where the Tangkhul Naga population is the majority.

QUESTION 7

With reference to Delhi’s Morphological Ridge, consider the following statements:

1. It represents the terminal stretch of the ancient Vindhyan hill range within Delhi.

2. It works as a green lung for the capital and a natural barrier against hazards such as desertification and pollution.

3. The region is largely composed of tropical dry thorn forests, featuring sparse tree cover, thorny shrubs, and vegetation adapted to drought conditions.

How many of the statements given above are correct?

(a) Only one

(b) Only two

(c) All three

(d) None

Ans B

Explanation

• The Delhi Ridge forms the northernmost extension of the Aravalli range, not the Vindhyan hills. It stretches across the National Capital Region, entering Delhi from the Gurgaon side and extending all the way to the Yamuna floodplains. Hence, Statement 1 is incorrect.
• This ecologically crucial area acts as a natural barrier, helping to curb desertification from the west and absorb harmful pollutants, thereby serving as a green lung for the city. Hence, Statement 2 is correct.
• The Morphological Ridge area is dominated by tropical dry thorn forests, a biome typical of arid and semi-arid regions. It includes drought-resistant species, thorny vegetation, and stunted trees, reflecting the shallow soil depth and rocky terrain found in this zone. Hence, Statement 3 is correct.
• The area, although not formally notified as forest land in some parts, enjoys judicial protection due to its ecological significance and is considered an extension of the Delhi Ridge in terms of physical and biological features.

Must Read: Supreme Court Action On Delhi Morphological Ridge Violation

QUESTION 8

What are the reasons for the flooding in Bengaluru every year?

1. The city’s elevated terrain
2. Absence of a significant river system to naturally divert surplus water
3. Urban development on former lake beds
4. Inadequate and outdated stormwater drainage infrastructure

Select the correct answer using the codes given below:

(a) 1 and 2 only

(b) 2 and 3 only

(c) 2, 3 and 4

(d) 1, 2, 3 and 4

Ans D

Explanation

Bengaluru has been witnessing seasonal urban flooding, which is becoming more frequent and severe due to multiple natural and man-made factors:

• The city is located at an elevation of approximately 900 meters above sea level. While elevation can help in natural drainage, the plateau-like structure and lack of slope in many areas result in water accumulation, especially in low-lying regions. Hence, Statement 1 is correct:
• Unlike cities situated on riverbanks (like Delhi on the Yamuna or Kolkata on the Hooghly), Bengaluru lacks a major river, meaning excess rainwater has no natural channel to exit the city. Hence, Statement 2 is correct
• Rapid urban expansion has led to encroachment on lake beds and connecting valley zones. Iconic tech parks and residential layouts, including ST Bed Layout and Manyata Tech Park, were developed on such ecologically sensitive zones. Historically, the city had over 1,450 lakes, which served as natural rainwater reservoirs. Now, only about 190 lakes remain, and many are partially filled or disconnected. Hence, Statement 3 is correct:
• The stormwater drain (SWD) system is no longer sufficient for the city’s growing population and increased rainfall events. Experts note that several SWDs have vanished due to construction or been blocked by debris and waste, especially along areas like Hosur Road and Electronic City. Hence, Statement 4 is correct

QUESTION 9

What is the correct sequence of the lion population (top to bottom) according to the 2025 Lion census?

1. Girnar Wildlife Sanctuary

2. Gir National Park and surrounding area

3. Mitiyala Wildlife Sanctuary

4. Savarkundla Wildlife Sanctuary

Select the correct answer using the codes given below:

(a) 1—2—4—3

(b) 2—1—4—3

(c) 1—2—3—4

(d) 2—1—3—4

Ans D

Explanation

— The most recent population assessment exercise in Gujarat found 891 lions, representing a 32% increase in population since 2020. Lions’ range has grown by 17% over the last five years, from 30,000 to 35,000 square kilometres, and they currently cover 58 talukas (up from 53 in 2020) throughout 11 districts.

— Asiatic lions have recovered dramatically from a population of less than 200 in the 1960s, when their last home in Gir was designated for special protection. For the most part, this progress has been long and steady—the population did not reach 300 until 1995, when the lion broke free from the shelter of the woodlands.

Lion Census data.

— The correct sequence is Gir National Park and surrounding area, Girnar Wildlife Sanctuary, Mitiyala Wildlife Sanctuary and Savarkundla Wildlife Sanctuary.

Must Read: Gujarat Forest Department Released 16th Asiatic Lion Census (2025)

QUESTION 10

With reference to the Konkan Railways (KR), consider the following statements:

1. It was established in 1990 to carry out the difficult task of constructing railway lines through the rocky Western Ghats.

2. The Konkan Railway (KR) spreads over Maharashtra and Goa only.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Ans A

Explanation

• The Konkan Railway Corporation Limited (KRCL) was established in 1990 as a special purpose vehicle under the Ministry of Railways. Its core mandate was to carry out the technically demanding construction of a railway line through the Western Ghats, known for their rocky terrain, steep gradients, and challenging monsoon weather conditions. Hence, Statement 1 is correct:
• While the Konkan Railway does pass through Maharashtra and Goa, its route extends well beyond these two states. The line originates from Roha in Maharashtra and passes through Goa and Karnataka, eventually reaching Mangaluru. It also connects to parts of coastal Kerala. Hence, the KR is a multi-state railway corridor that spans across Maharashtra, Goa, Karnataka, and Kerala. Hence, Statement 2 is not correct

Additional Insight The Konkan Railway officially began operations in January 1998. It was developed as a joint venture, with the Government of India holding a 51% stake, and the rest shared among Maharashtra (22%), Karnataka (15%), Goa and Kerala (6% each). Recently, the Government of Maharashtra approved the integration of KRCL with Indian Railways, aligning with earlier approvals from Goa, Karnataka, and Kerala — paving the way for a complete merger.

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