Science chapter practice

General Science Mixed Concepts MCQs

Practise 80+ General Science Mixed Concepts MCQs for UPSC Prelims in Science, including 38+ previous year questions. The sample set below is shown with correct answers and explanations.

80
questions
38
PYQs
12
visible samples

Sample General Science Mixed Concepts questions

12 sample questions are shown here; sign up free to practise all 80.

Q1ScienceGeneral Science Mixed ConceptsPYQ 2023

Some microorganisms can grow in environments with temperature above the boiling point of water. Some can grow below the freezing point of water. Some can grow in highly acidic environments with a pH below 3. How many of the above statements are correct?

  • AOnly one
  • BOnly two
  • CAll threeCorrect
  • DNone

Explanation

Correct. Thermophiles thrive above 100 °C near hydrothermal vents, psychrophiles grow below 0 °C in polar ice, and acidophiles flourish at pH below 3 in acid mine drainage.

Q2ScienceGeneral Science Mixed ConceptsPYQ 2022

Consider the following statements in respect of probiotics: 1. Probiotics are made of both bacteria and yeast. 2. The organisms in probiotics are found in foods we ingest but they do not naturally occur in our gut. 3. Probiotics help in the digestion of milk sugars. Which of the statements given above is/are correct?

  • A1 only
  • B2 only
  • C1 and 3Correct
  • D2 and 3

Explanation

Correct. Probiotics include both bacteria (e.g., Lactobacillus) and yeast (e.g., Saccharomyces boulardii), and they aid in digesting lactose. Statement 2 is wrong because probiotic organisms naturally inhabit the gut.

Q3ScienceGeneral Science Mixed ConceptsPYQ 2021

Consider the following: 1. Bacteria 2. Fungi 3. Virus Which of the above can be cultured in an artificial/synthetic medium?

  • A1 and 2 onlyCorrect
  • B2 and 3 only
  • C1 and 3 only
  • D1, 2 and 3

Explanation

Correct. Bacteria and fungi can be grown on synthetic nutrient media. Viruses are obligate intracellular parasites and require living host cells, so they cannot be cultured on artificial media alone.

Q4ScienceGeneral Science Mixed ConceptsPYQ 2021

In the nature, which of the following is/are most likely to be found surviving on a bare rock? 1. Fern 2. Lichen 3. Moss 4. Mushroom Select the correct answer using the code given below.

  • A1 and 4 only
  • B2 only
  • C2 and 3Correct
  • D1, 3 and 4

Explanation

Correct. Lichens and mosses are pioneer species capable of colonising bare rock. Lichens secrete acids that slowly weather rock, and mosses can anchor on minimal substrate.

Q5ScienceGeneral Science Mixed ConceptsPYQ 2014

Among the following organisms, which one does not belong to the class of other three?

  • ACrabCorrect
  • BMite
  • CScorpion
  • DSpider

Explanation

Correct. Mites, scorpions and spiders are all arachnids (class Arachnida), whereas crabs belong to the class Malacostraca (crustaceans).

Q6ScienceGeneral Science Mixed ConceptsPYQ 2013

Consider the following minerals: 1. Calcium 2. Iron 3. Sodium Which of the minerals given above is/are required by the human body for the contraction of muscles?

  • A1 only
  • B2 and 3 only
  • C1 and 3 only
  • D1, 2 and 3Correct

Explanation

Correct. Calcium triggers the actin-myosin interaction for contraction, sodium enables nerve impulse transmission to muscles, and iron is vital for oxygen delivery to muscle tissue via haemoglobin.

Q7ScienceGeneral Science Mixed ConceptsPYQ 2013

Consider the following animals: 1. Sea cow 2. Sea horse 3. Sea lion Which of the above is/are mammal/mammals?

  • A1 only
  • B1 and 3 onlyCorrect
  • C2 and 3 only
  • D1, 2 and 3

Explanation

Correct. Sea cows (dugongs/manatees) and sea lions are marine mammals. Sea horses are bony fish of the genus Hippocampus.

Q8ScienceGeneral Science Mixed ConceptsPYQ 2010

From the point of view of evolution of living organisms, which one of the following is the correct sequence of evolution?

  • AOtter — Tortoise — Shark
  • BShark — Tortoise — OtterCorrect
  • CTortoise — Shark — Otter
  • DShark — Otter — Tortoise

Explanation

Correct. Fish (shark) evolved first, followed by reptiles (tortoise), and then mammals (otter) — matching the progression of vertebrate evolution.

Q9ScienceGeneral Science Mixed ConceptsPYQ 2008

Assertion (A): In the human body, the liver has an important role in fat digestion. Reason (R): Liver produces two important fat-digesting enzymes. Select the correct answer.

  • ABoth A and R are individually true and R is the correct explanation of A
  • BBoth A and R are individually true but R is not the correct explanation of A
  • CA is true but R is falseCorrect
  • DA is false but R is true

Explanation

Correct. The liver aids fat digestion by producing bile which emulsifies fats, making A true. However, the liver does not produce fat-digesting enzymes (lipases come from the pancreas), making R false.

Q10ScienceGeneral Science Mixed ConceptsPYQ 2007

How do most insects respire?

  • AThrough skin
  • BThrough gills
  • CBy lungs
  • DBy tracheal systemCorrect

Explanation

Correct. Insects respire through a network of tracheae — tiny tubes that open at spiracles on the body surface and deliver oxygen directly to tissues.

Q11ScienceGeneral Science Mixed ConceptsPYQ 2007

Which one of the following is the correct sequence in the order of decreasing length of the three structural parts of the small intestine in the human body?

  • AJejunum — Duodenum — Ileum
  • BIleum — Duodenum — Jejunum
  • CIleum — Jejunum — DuodenumCorrect
  • DJejunum — Ileum — Duodenum

Explanation

Correct. The ileum (~3.5 m) is the longest, followed by the jejunum (~2.5 m), and the duodenum (~25 cm) is the shortest part of the small intestine.

Q12ScienceGeneral Science Mixed ConceptsPYQ 2007

In human beings, normally in which one of the following parts does the sperm fertilize the ovum?

  • ACervix
  • BFallopian tubeCorrect
  • CLower part of uterus
  • DUpper part of uterus

Explanation

Correct. Fertilization typically occurs in the ampulla of the fallopian tube (oviduct), where the sperm meets the ovum after ovulation.

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How many General Science Mixed Concepts MCQs are available for UPSC Prelims practice?
PrelimsAI currently has 80+ General Science Mixed Concepts MCQs under Science. This page shows 12 sample questions in full.
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38+ questions in this chapter are tagged as UPSC Prelims PYQs. PYQs are prioritised in the visible sample set when available.
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