473 previous year UPSC Prelims Science and Technology questions are on this page, from 1996 to 2025, in 21 chapters. Biology: Zoology is the largest, followed by Miscellaneous (energy, vehicles and materials), Botany, Space and ICT. Recent papers lean on applied technology in the news, while older ones lean on school-level physics, chemistry and biology. Filter by chapter to revise one area at a time.
Explanations state facts as of the year each question was asked; words like “recently” refer to that year.
Showing 471–473 of 473 questions
Besides proteins and carbohydrates, milk is a rich source of calcium and potassium, which are essential for strong bones, teeth, and maintaining fluid balance. Calcium is essential for bone health, muscle function and nerve signaling. Potassium is an important electrolyte that helps regulate fluid balance, muscle contractions and nerve signals.
Subcutaneous fat is a layer of fat located just beneath the skin. It primarily acts as an insulator which reduces heat loss from the body by trapping heat and maintaining body temperature. This insulation is particularly beneficial in cold environments, helping to conserve energy and prevent hypothermia.
Option (c) is correct: The major chemical compound that constitutes kidney stones is Calcium Oxalate. These stones are common and can cause severe pain during urination. Calcium oxalate is formed when calcium in the urine binds with oxalate, a compound found in certain foods (e.g., spinach, nuts) or produced as a by-product of metabolism. High concentrations of calcium and oxalate in urine, combined with low fluid intake, promote the crystallization of calcium oxalate. Options (a), (b), and (d) are incorrect: Urea is not a major component of kidney stones because it is a waste product of protein metabolism that is typically excreted in the urine. Other types of kidney stones can contain calcium carbonate, calcium phosphate, uric acid, or struvite, but calcium oxalate stones are the most common. Factors such as dehydration, high oxalate intake, and certain medical conditions can increase the risk of kidney stone formation.
| Q | UPSC year | Correct answer |
|---|---|---|
| 471 | 1996 | (b) calcium and potassium |
| 472 | 1996 | (a) Loss of heat from the body |
| 473 | 1996 | (c) calcium oxalate |
This page covers 473 previous year UPSC Prelims GS Paper-I questions on Science and Technology, asked from 1996 to 2025. Each has the correct answer and an explanation.
Biology: Zoology has the most with 115 questions, then Miscellaneous with 68, Biology: Botany with 37, Space and Space Technology with 36 and Information and Communication Technology with 32.
Take the technology chapters first, because recent papers favour them, then use the Physics, Chemistry and Biology chapters for basics. Each chapter page lists the facts UPSC has tested and has an answer key.
Questions whose explanations depend on chemical formulas or equations that could not be shown correctly were left out, rather than risk a wrong formula. The questions that remain have clear explanations in plain words.
