Daily Prelims MCQs - Sci-Tech, Environment and Geography - 7th October 2025
- TPP
- Oct 8
- 9 min read
Welcome to your Daily UPSC Prelims Current Affairs MCQs – 7th October 2025. This is part of our subject-wise daily series where Tuesday is dedicated to Science & Technology, Environment, and Geography—linking conceptual understanding with contemporary developments for integrated Prelims–Mains preparation.
Key topics include the Sir Creek dispute and its implications for EEZ delimitation, the newly proposed Acoustic Vehicle Alerting System (AVAS) for electric vehicles, and the fundamentals of climate models used for predicting long-term climate change.
You’ll also cover the Carlsberg Ridge in the Indian Ocean, the carbon fertilisation effect driving Amazon tree growth, and the prospects and challenges of hydrogen as clean fuel.
Static–dynamic linkages are reinforced through concepts like fundamental forces of nature, hypoxia and hypothermia, uranium enrichment, and AstroSat’s multi-wavelength space exploration.
Consistent practice with these MCQs will sharpen your concept recall, build GS Paper 1 & 3 linkages, and enhance your readiness for the UPSC Prelims 2026’s analytical trend—connecting news to science, environment, and innovation seamlessly.
Click Here to read the Monthly Current Affairs Pointers (CAP).
QUESTION 1
With reference to the Sir Creek, consider the following statements:
It is a 96-km tidal estuary located between West Bengal in India and Bangladesh.
It flows into the Bay of Bengal
It directly impacts maritime boundary delimitation and Exclusive Economic Zones (EEZs).
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer (a)
Explanation:
Union Defence Minister Rajnath Singh warned Pakistan over the Sir Creek region, reiterating India’s firm stance on the subject of its territorial integrity.
Sir Creek was originally named ‘Ban Ganga’ and got its present name after a British official. The creek is a 96-km tidal estuary along the India-Pakistan border, located between Gujarat in India and Sindh in Pakistan. Hence, statement 1 is not correct.
It flows into the Arabian Sea and lies at the heart of a prolonged dispute over maritime boundaries, control of natural resources, and strategic dominance. Hence, statement 2 is not correct.
It directly impacts maritime boundary delimitation and Exclusive Economic Zones (EEZs) in the Arabian Sea. EEZs or exclusive economic zones are areas of the ocean, generally extending 200 nautical miles (230 miles) beyond a nation’s territorial sea, within which they have jurisdiction over both living and non-living resources. Hence, statement 3 is correct.
QUESTION 2
The Acoustic Vehicle Alerting System (AVAS) is related to:
(a) e-vehicles
(b) Hydrogen vehicles
(c) CNG vehicles
(d) Petrol vehicle
Answer (a)
Explanation:
In a step to curb road accidents involving electrified vehicles, the Ministry of Road Transport and Highways (MoRTH) has proposed an acoustic vehicle alerting system (AVAS) for all electric cars, buses and trucks.
AVAS is a device that will generate sound if the vehicle is moving at a speed up to 20 kmph to alert road users, especially pedestrians.
According to the draft notification issued on September 23, all new models of electric vehicles, including both passengers and goods, manufactured after October 1, 2026, will have to be fitted with Acoustic Vehicle Alerting System to meet the requirements with regard to audibility. For the existing models, the cut-off date is October 1, 2027 and after that they too will have to install AVAS in the vehicles.
QUESTION 3
With reference to the climate models, consider the following statements:
It is a computer simulation that uses mathematical formulae and algorithms to replicate the Earth’s climate system.
It can forecast how variables such as temperature and humidity will change over time under different scenarios.
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
Answer (c)
Explanation:
A climate model is a computer simulation that uses mathematical formulae and algorithms to replicate how the Earth’s climate system — including the atmosphere, ocean, land and ice — works. Hence, statement 1 is correct.
These models are built on the principles of physics, chemistry, and biology, and are designed to simulate or mimic the interactions between the atmosphere, oceans, land surface, and ice.
Climate models can forecast how variables such as temperature and humidity will change over time under different scenarios, like increased greenhouse gas emissions or changes in land use. Simply put, they allow scientists to test hypotheses and draw conclusions on past and future climate systems. Hence, statement 2 is correct.
This also helps them to determine if abnormal weather events like extreme heavy rainfall are a result of changes in climate or just part of routine climate variation.
QUESTION 4
The carlsberg-ridge was recently in the news. It is located in:
(a) Mediterranean Sea
(b) Pacific Ocean
(c) Atlantic Ocean
(d) Indian Ocean
Answer (d)
Explanation:
The Carlsberg Ridge is a major segment of the mid-ocean ridge system in the Indian Ocean, formed by seafloor spreading between the Indian Plate and the Somali Plate.
It is estimated that the current phase of opening of the Carlsberg Ridge began at about 40 million years ago following a major plate reorganisation and its average spreading rate is of 2.4 to 3.3 cm/year.
The ridge has a rough flanking topography and a median valley, which are the characteristics of slow-spreading ridges.
The ridge is known to host hydrothermal vent systems, potential sites of PMS deposits. India has conducted scientific research on these systems during the past three decades.
Strategically, the Carlsberg Ridge is particularly important because it is located much closer to India (around 2 degree north) compared with the Central and Southwest Indian Ridges (around 26 degree south).
QUESTION 5
Consider the following statements:
Statement 1: The average size of trees in the Amazon rainforest has been steadily increasing due to the rising levels of carbon dioxide (CO2) in the atmosphere.
Statement 2: The rise of CO2 levels can benefit tree growth because of a phenomenon known as the carbon fertilisation effect.
Which one of the following is correct in respect of the above statements?
(a) Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation for Statement 1.
(b) Both Statement 1 and Statement 2 are correct and Statement 2 is not the correct explanation for Statement 1.
(c) Statement 1 is correct but Statement 2 is incorrect.
(d) Statement 1 is incorrect but Statement 2 is correct.
Answer (a)
Explanation:
The average size of trees in the Amazon rainforest has been steadily increasing due to the rising levels of carbon dioxide (CO2) in the atmosphere, according to a new study. The trees are increasing in size by more than three per cent every ten years, the analysis said. Hence, statement 1 is correct.
The study, ‘Increasing tree size across Amazonia’, was published in the journal Nature Plants on September 25. It was carried out by an international team of around 100 scientists from more than 60 universities around the world, including those from South America and the United Kingdom.
Usually, the average diameter of trees in an area of undisturbed old-growth forest stays roughly the same, as saplings take the place of fallen big trees and grow. Scientists believe that in the case of the Amazon rainforests, trees did not follow this trend due to a rise in atmospheric CO2, which increased by nearly a fifth in the last 30 years.
The rise of CO2 levels can benefit tree growth because of a phenomenon known as the carbon fertilisation effect. More CO2 in the atmosphere increases the rate of photosynthesis, leading to increased growth in some plants. Hence, statement 2 is correct.
Both Statement 1 and Statement 2 are correct and Statement 2 is the correct explanation for Statement 1.
QUESTION 6
With reference to Hydrogen as fuel, consider the following statements:
Hydrogen, when combined with oxygen in a fuel cell, produces electricity and releases only water vapour as exhaust.
It takes too much time to refuel compared to batteries.
The biggest challenge in implementing hydrogen as fuel is its high density.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer (a)
Explanation:
Hydrogen is appealing because it burns cleanly: when combined with oxygen in a fuel cell, it produces electricity and releases only water vapour as exhaust. Hence, statement 1 is correct.
Unlike batteries, which must be recharged, hydrogen can be refueled quickly — much like petrol or diesel — making it attractive for long-haul trucks, buses, ships, and potentially even planes. Hence, statement 2 is not correct.
And hydrogen isn’t just about cars. Properly harnessed, it could power homes, balance electricity grids, and store renewable energy from solar and wind farms for months at a time, smoothing out supply when the sun isn’t shining and the wind isn’t blowing. In principle, it could provide a backbone for a carbon-free society.
The biggest challenge in implementing hydrogen as fuel is its low density. At room temperature, one kilogram of hydrogen would fill about 11 cubic meters — the size of a small bedroom. Petrol, by contrast, packs the same mass into just over a liter. Hence, statement 3 is not correct.
QUESTION 7
Which of the following are fundamental forces of nature?
Electromagnetic force
Gravity force
Strong nuclear force
Weak nuclear force
Select the correct answer using the codes given below:
(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2, 3 and 4
Answer (d)
Explanation:
Electromagnetism is the fundamental force that unites electricity and magnetism.
It is one of the four fundamental forces of nature – alongside gravity, the strong nuclear force, and the weak nuclear force. Unlike gravity, which only attracts, the electromagnetic force both attracts and repels.
It governs the behaviour of charged particles, binding electrons to nuclei to form atoms and, in turn, molecules. Without it, chemistry would not exist, and neither would life.
QUESTION 8
With reference to hypoxia and hypothermia, consider the following statements:
Hypoxia is caused by inadequate oxygen.
Hypothermia is a fall in core body temperature to a level where normal physical and brain functions are impaired.
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
Answer (c)
Explanation:
A 13-year-old boy from Kunduz, Afghanistan, wanted to travel to Iran. So, he managed to sneak into an aircraft’s rear wheel well at the Kabul airport, except that the plane — operating Kam Air flight RQ4401 — was bound for Delhi, not Tehran. For the flight duration of over 90 minutes, the boy was in the wheel well, even as the aircraft cruised at over 30,000 feet where outside air pressure and temperature plummet. Miraculously, he survived the ordeal, landing seemingly unharmed at the Delhi airport, where he was spotted by some airport staff. In the evening, he was sent back on the same aircraft to Kabul, this time in the plane’s passenger cabin.
Hypoxia is caused by inadequate oxygen, while hypothermia is a fall in core body temperature to a level where normal physical and brain functions are impaired. Severe levels of either can lead to unconsciousness, and even death. Hence, statements 1 and 2 are correct.
QUESTION 9
With reference to Uranium, consider the following statements:
It is the most common fissile material.
More than 99 per cent of naturally occurring uranium is U-235.
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
Answer (a)
Explanation:
Uranium is the most common fissile material used in these processes, either to make electricity in civilian reactors or in weapons. Hence, statement 1 is correct.
But naturally occurring uranium is not fissile, meaning its nucleus is relatively stable and does not readily break up into nuclei of smaller elements.
Naturally occurring uranium is primarily U-238, a slightly heavier isotope of the element. It is the slightly lighter uranium, called U-235, which is fissile. More than 99 per cent of naturally occurring uranium is U-238. Hence, statement 2 is not correct.
Enrichment is the process of increasing the concentration of U-235 in a uranium sample.
QUESTION 10
With reference to the AstroSat, consider the following statements:
It is India’s first multi wavelength space observatory dedicated for astronomy.
It was launched aboard the PSLV-C30.
It is capable of observing the universe simultaneously in a broad energy range from ultraviolet (UV) rays.
How many of the statements given above are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer (c)
Explanation:
On September 28, 2025 AstroSat India’s first multi wavelength space observatory dedicated to astronomy, completed a decade filled with groundbreaking discoveries and dedicated service to the global scientific community. Hence, statement 1 is correct.
AstroSat was launched aboard the PSLV-C30 on September 28, 2015 from the Satish Dhawan Space Centre. Hence, statement 2 is correct.
AstroSat is capable of observing the universe simultaneously in a broad energy range from ultraviolet (UV), visible, and high energy X-rays, rendering it a powerful tool for understanding various cosmic phenomena. Hence, statement 3 is correct.
Previous Daily UPSC Prelims MCQs Set
30th Sept 2025 - Sci-Tech, Env and Geo MCQs
Previous Week Current Affairs MCQs Set
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