Q200. Identify the valid food-chain sequence.
[UPSC CDS (II) General Knowledge (2026)]
(A) Grass → Fish → Goat
(B) Grass → Insects → Frog
(C) Goat → Cow → Elephant
(D) Tiger → Lion → Grass
Answer: (B) Grass → Insects → Frog
Explanation: A food chain begins with primary producers, here grass, which is eaten by insects. Frogs consume many insects and form the next trophic level. The remaining sequences do not describe a plausible producer-to-herbivore-to-carnivore pathway.
Q199. Which measure contributes to reducing environmental problems?
[UPSC CDS (II) General Knowledge (2026)]
(A) Biomagnification
(B) Accelerated eutrophication
(C) Release of nuclear waste
(D) Sorting different waste categories for disposal
Answer: (D) Sorting different waste categories for disposal
Explanation: Segregating waste at source enables material recovery, safe handling of hazardous fractions and appropriate treatment. Biomagnification, eutrophication and uncontrolled nuclear-waste release instead describe environmental hazards. Proper waste separation is a basic component of integrated solid-waste management.
Q198. Which of the following is NOT a biological pest-control agent?
[UPSC CDS (II) General Knowledge (2026)]
(A) Bacillus thuringiensis
(B) Ladybird beetle
(C) Trichoderma
(D) Aphid
Answer: (D) Aphid
Explanation: Aphids are common sap-sucking crop pests rather than organisms normally deployed to control other pests. Bacillus thuringiensis kills susceptible insect larvae, ladybirds prey on aphids, and Trichoderma fungi suppress several plant pathogens in biological control.
Q197. Which programme listed below is associated with India’s conservation of wild big cats?
[UPSC CDS (II) General Knowledge (2026)]
(A) Humpback Whale Project
(B) International Big Cat Alliance
(C) International Gorilla Conservation Programme
(D) International Rhino Foundation
Answer: (B) International Big Cat Alliance
Explanation: India initiated the International Big Cat Alliance to strengthen cooperation on conserving seven big-cat species and their habitats. The other programmes concern whales, gorillas or rhinoceroses and are not the named Indian big-cat conservation initiative tested in the paper.
Q196. Regarding mangroves:
1. They form natural buffers against cyclones and coastal erosion.
2. India introduced MISHTI for mangrove habitats and livelihoods.
Which is correct?
[UPSC CDS (II) General Knowledge (2026)]
(A) 1 only
(B) 2 only
(C) Both 1 and 2
(D) Neither 1 nor 2
Answer: (C) Both 1 and 2
Explanation: Mangrove belts reduce wave impacts, trap sediments and protect exposed shorelines. India’s MISHTI initiative supports mangrove plantations and restoration alongside tangible incomes for coastal communities. Both the ecological function and the stated policy connection are accurate.
2025
Q195. Cigarette filters, plastic eyeglass lenses and car tyres were listed. How many of these products can contain plastic or synthetic polymers?
[UPSC CSE Prelims GS Paper I (2025)]
(A) Only one
(B) Only two
(C) All three
(D) None
Answer: (C) All three
Explanation: Cigarette filters typically contain cellulose acetate, many optical lenses use polymer resins, and tyres include synthetic elastomers. These materials can release plastic-related waste or particles during use and disposal, so all three examples are relevant.
Q194. Consider activated carbon:
I. It treats polluted effluent.
II. Its high surface area helps adsorb heavy metals.
III. It can be manufactured from carbon-rich wastes.
Which relation is valid?
[UPSC CSE Prelims GS Paper I (2025)]
(A) Both II and III are correct and explain I
(B) Both are correct but only one explains I
(C) Only one is correct and explains I
(D) Neither is correct
Answer: (A) Both II and III are correct and explain I
Explanation: Activated carbon removes dissolved pollutants through its extensive porous surface. Agricultural and industrial carbon-rich residues can serve as inexpensive precursor materials, making treatment attractive. Both adsorption performance and practical manufacture help explain why it is used in remediation.
Q193. In cement production,
I. the industry contributes over 5% of global CO₂ emissions;
II. silica-bearing clay is mixed with limestone;
III. limestone calcination yields lime.
Which explanation is appropriate?
[UPSC CSE Prelims GS Paper I (2025)]
(A) Both II and III explain I
(B) II and III are correct, but only III explains I
(C) Only one is correct and explains I
(D) Neither is correct
Answer: (B) II and III are correct, but only III explains I
Explanation: Clay and limestone are both used in making cement clinker, but simply combining them does not explain significant emissions. Heating limestone releases carbon dioxide during calcination. This process, together with fuel combustion, gives cement manufacture its major carbon footprint.
Q192. With respect to COP28’s Declaration on Climate and Health, which claim correctly explains India’s decision not to sign?
[UPSC CSE Prelims GS Paper I (2025)]
(A) It became compulsory law on signing
(B) It legally required immediate healthcare closure
(C) India raised concern about health-system resilience; the declaration is voluntary
(D) Signing mandates fossil-fuel use
Answer: (C) India raised concern about health-system resilience; the declaration is voluntary
Explanation: The declaration was non-binding, so signing would not automatically create enforceable decarbonisation duties. India nevertheless expressed concern over how rapid health-sector changes might affect service delivery and resilience. This makes the binding-law explanation incorrect.
Q191. For Paris Agreement Article 6:
II. It covers carbon markets.
III. It enables cooperation outside market mechanisms.
How do these relate to its international importance?
[UPSC CSE Prelims GS Paper I (2025)]
(A) Both II and III are true and explain its significance
(B) Both true but only one relevant
(C) Only one true
(D) Neither true
Answer: (A) Both II and III are true and explain its significance
Explanation: Article 6 provides frameworks for internationally transferred mitigation outcomes and a supervised crediting mechanism, while also recognising non-market cooperation. These alternatives help countries work toward climate commitments and explain the article’s importance in negotiations.
