Biological Classification — Class 11 MCQs with Answers
Class 11 CBSE Biology · Chapter 2
90 practice questions · 30 Easy · 30 Medium · 30 Hard · Updated
Practise the most important Class 11 CBSE Biology questions from Chapter 2, "Biological Classification". You get 9 timed quizzes made from 90 NCERT-based MCQs, with answers and explanations. The questions are split into 30 Easy, 30 Medium and 30 Hard. Warm up on the basics, then move on to the exam-level questions that set top scorers in CBSE & Maharashtra HSC Board exams, MHT-CET and NEET UG apart.
To score well in "Biological Classification", focus on diagrams, key terms and knowing NCERT line by line. Each MCQ here is timed and uses exam-style marking (+4 correct, −1 wrong, 0 skipped). This trains you to stay accurate under time pressure, as real papers need. Every question has a short explanation, so a wrong answer becomes a quick lesson. It is the fastest way to fix gaps before a test.
Use this chapter for focused revision. Start with the Easy set to check your basics on Biological Classification, then move to Medium and Hard to practise applying them. Your accuracy, streaks and XP save automatically. This chapter also adds to your overall Class 11 Biology mastery score. 14 sample questions are solved in full below, with the answer and a worked explanation. Sign in free to start practising.
Key concepts: Biological Classification (Class 11 Biology)
Whittaker's five-kingdom system sorts life by cell structure, body organisation, nutrition and phylogeny into Monera, Protista, Fungi, Plantae and Animalia. This chapter details each kingdom's diagnostic features and the acellular oddities — viruses, viroids, prions and lichens — that fall outside the scheme.
- Five-kingdom system
- Whittaker (1969) used cell type, body organisation, nutrition, reproduction and phylogeny to define Monera, Protista, Fungi, Plantae and Animalia.
- Two-kingdom limitation
- Linnaeus's Plantae/Animalia split ignored prokaryote–eukaryote and uni-/multicellular differences and lumped green and non-green organisms together.
- Monera
- Prokaryotes with no true nucleus or membrane-bound organelles — bacteria, cyanobacteria, archaebacteria and mycoplasma. Nutrition autotrophic or heterotrophic.
- Archaebacteria
- Bacteria of extreme habitats — halophiles, thermoacidophiles and methanogens. A distinctive cell wall lets them survive high salt, heat and acidity.
Biological Classification — important questions & MCQs with answers (Class 11 Biology)
14 solved questions from this chapter's difficulty levels, each with its answer and explanation. The other 76 are timed and scored when you sign in.
- Q1Easy
Five-kingdom classification was proposed by:
A.MendelB.LinnaeusC.DarwinD.Whittaker✓ CorrectAnswer: D. Whittaker
Explanation: Whittaker proposed the five-kingdom system in 1969 (Monera, Protista, Fungi, Plantae, Animalia). Linnaeus gave the two-kingdom system; Mendel and Darwin worked on heredity and evolution, not taxonomy.
- Q2Easy
The earliest two-kingdom classification was proposed by:
A.HaeckelB.WhittakerC.Linnaeus✓ CorrectD.MargulisAnswer: C. Linnaeus
Explanation: Linnaeus's two-kingdom system (Plantae and Animalia) predates Haeckel's three-kingdom addition of Protista, Copeland's four-kingdom Monera split, and Whittaker's later five-kingdom scheme.
- Q3Easy
The term 'virus' (meaning poisonous fluid) was coined by:
A.Pasteur✓ CorrectB.BeijerinckC.IvanowskyD.StanleyAnswer: A. Pasteur
Explanation: NCERT credits Pasteur with the name virus, from the Latin for venom or poisonous fluid. Beijerinck's 1898 contribution was a different term — Contagium vivum fluidum, 'infectious living fluid' — while Ivanowsky showed the agent passed through bacteria-proof filters.
- Q4Easy
Bacteria belong to kingdom:
A.ProtistaB.Monera✓ CorrectC.PlantaeD.FungiAnswer: B. Monera
Explanation: Bacteria are prokaryotes with no nuclear membrane or membrane-bound organelles, so Whittaker's scheme places them in Monera, not Protista, which is reserved for unicellular eukaryotes like amoeba.
- Q5Easy
Three-domain system was proposed by:
A.Carl Woese✓ CorrectB.MargulisC.WhittakerD.HaeckelAnswer: A. Carl Woese
Explanation: Carl Woese's 1990 three-domain system split Monera into Bacteria and Archaea based on rRNA sequence differences, adding Eukarya as the third domain — a refinement Whittaker's 1969 scheme did not attempt.
- Q6Easy
TMV (Tobacco Mosaic Virus) was crystallised by:
A.BeijerinckB.IvanowskyC.PasteurD.W. M. Stanley✓ CorrectAnswer: D. W. M. Stanley
Explanation: W.M. Stanley crystallised Tobacco Mosaic Virus in 1935, proving it was largely protein and settling debate about whether viruses were living — Ivanowsky and Beijerinck had only studied its infectivity, not its structure.
- Q7Medium
Fungi cell wall is made of:
A.PeptidoglycanB.CelluloseC.Chitin✓ CorrectD.SilicaAnswer: C. Chitin
Explanation: Fungal cell walls are built of chitin, a nitrogen-containing polysaccharide, unlike the cellulose walls of plants and algae or the peptidoglycan walls of bacteria — the wall material is the giveaway.
- Q8Medium
Whittaker placed organisms in five kingdoms primarily on the basis of:
A.Only cell typeB.Only nutritionC.Cell type, body organisation, nutrition, reproduction, phylogeny✓ CorrectD.Only reproductionAnswer: C. Cell type, body organisation, nutrition, reproduction, phylogeny
Explanation: Whittaker used five criteria together — cell structure, body organisation, mode of nutrition, mode of reproduction, and phylogenetic relationships — not any single one alone, to separate the five kingdoms.
- Q9Medium
Viruses are considered:
A.AnimalsB.Fully livingC.PlantsD.On the borderline of living and non-living✓ CorrectAnswer: D. On the borderline of living and non-living
Explanation: Viruses sit on the living/non-living border: outside a host they are inert, crystallisable particles with no metabolism, but inside a host cell they hijack machinery to replicate.
- Q10Medium
Archaebacteria differ from other bacteria in:
A.Having mitochondriaB.Having nucleusC.Being eukaryoticD.Cell wall structure (lack peptidoglycan)✓ CorrectAnswer: D. Cell wall structure (lack peptidoglycan)
Explanation: Archaebacteria lack the peptidoglycan found in true bacterial cell walls, instead having pseudopeptidoglycan and distinctive lipids — this biochemical difference is why they are not eukaryotic despite unusual habitats.
- Q11Medium
Lichens are good indicators of:
A.SO₂ pollution✓ CorrectB.Water pollutionC.Noise pollutionD.Light pollutionAnswer: A. SO₂ pollution
Explanation: Lichens are extremely sensitive to sulphur dioxide and vanish first from polluted air, so their presence or absence is used as a bioindicator of SO2/air pollution rather than water, noise or light pollution.
- Q12Hard
Kingdom Protista is mainly:
A.Unicellular eukaryotes✓ CorrectB.Multicellular plantsC.ProkaryotesD.FungiAnswer: A. Unicellular eukaryotes
Explanation: Kingdom Protista is Whittaker's group for unicellular eukaryotes such as amoeba and paramecium — a true nucleus separates them from prokaryotic Monera, and being single-celled separates them from multicellular Plantae.
- Q13Hard
Assertion: Fungi are placed in a separate kingdom. Reason: They have chitinous cell walls and are heterotrophic.
A.A true, R falseB.Both A and R true; R does not explain AC.Both A and R true; R explains A✓ CorrectD.A false, R trueAnswer: C. Both A and R true; R explains A
Explanation: Fungi form their own kingdom precisely because chitinous cell walls and obligate heterotrophy set them apart from plants (cellulose walls, autotrophic) and animals (no cell wall) — the reason directly justifies the assertion.
- Q14Hard
Lichens are symbiotic association of:
A.Animals and fungiB.Bacteria and plantsC.Algae and Fungi✓ CorrectD.Algae aloneAnswer: C. Algae and Fungi
Explanation: A lichen is a mutualistic partnership of a fungus (mycobiont) and a photosynthetic alga or cyanobacterium (phycobiont) — the fungus gives shelter and minerals, the alga supplies food, so neither partner alone counts.
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Start this chapter free →Biological Classification — FAQs
What are the key concepts in Class 11 Biology Biological Classification?+
Whittaker's five-kingdom system sorts life by cell structure, body organisation, nutrition and phylogeny into Monera, Protista, Fungi, Plantae and Animalia. This chapter details each kingdom's diagnostic features and the acellular oddities — viruses, viroids, prions and lichens — that fall outside the scheme. Key ideas include Five-kingdom system, Two-kingdom limitation, Monera, Archaebacteria.
What does Class 11 Biology Chapter 2 (Biological Classification) cover on XamBaaz?+
It has 90 NCERT-based MCQs on "Biological Classification": 30 Easy, 30 Medium and 30 Hard. Together they make 9 timed quizzes, and you never get the same set twice. Every question has an instant explanation. They help you prepare for CBSE & Maharashtra HSC Board exams, MHT-CET and NEET UG.
Are these "Biological Classification" questions free to practise?+
Yes. Sign in with Google to practise "Biological Classification" free. Full unlimited access is ₹999/year on a launch offer until 1 December 2026. No chapter is charged separately.
How should I revise "Biological Classification" for the exam?+
Start with the Easy quiz to check your basics, then try Medium and Hard to practise applying them. There are 9 timed quizzes on this chapter, so you can come back for a fresh set instead of one you have seen. Read each explanation, retry the questions you miss, and track your accuracy until it stays high.
Are these "Biological Classification" MCQs available with answers?+
Yes. 14 sample questions are shown here in full, each with the correct option and a step-by-step "Why" explanation. Sign in free with Google to start practising, with instant scoring.
Is there negative marking in the "Biological Classification" quizzes?+
Yes. The timed quizzes use exam-style marking: +4 for a right answer, −1 for a wrong one and 0 for a skip, the same negative marking as NEET UG. MHT-CET and CBSE board papers have no negative marking. Our mocks for those are scored their way.
What are the important questions from Biological Classification (Class 11 Biology)?+
The questions that matter most test Five-kingdom system, Two-kingdom limitation, Monera, Archaebacteria. This page shows 14 solved important MCQs with answers and explanations; all 90 questions on the chapter are available as timed quizzes once you sign in.
Is there an online quiz for Biological Classification?+
Yes — Class 11 Biology Biological Classification has timed online quizzes at Easy, Medium and Hard levels, with instant scoring and a worked explanation on every question. The first quiz on the chapter is free.