Biological Classification is a Class 11 Botany chapter in the NEET (UG) syllabus. NEET720 has 546 reviewed practice questions on it, each with a quick answer and a step-by-step explanation. The 8 questions below are free and fixed, so you can bookmark this page; the full chapter, plus mistake tracking and spaced revision, is in the app.
94
easy
377
medium
75
hard
Topics covered
Five Kingdom Classification · Kingdom Monera · Kingdom Protista · Kingdom Fungi · Viruses, Viroids, Prions and Lichens · Viroids · Angiosperm classification systems · Diversity in Living World · Two Kingdom vs Five Kingdom · Whittaker's classification logic · Fungi · Fungal life cycle · Five kingdoms · Gram staining · Viruses · Cyanobacteria · Lichens · Protista · Viruses and viroids · Bacteriophage structure · Sub-viral and acellular agents · Lichens and viruses · Five kingdoms and viruses · Monera · Virus/Monera boundary · Five kingdom system · Virus · Protista/Fungi boundary · Five Kingdom + Monera · Five Kingdom + Fungi · Protista + Fungi · Monera + Virus · Monera + Protista · Fungi + Virus · Monera + Fungi · Five Kingdom + Protista · Monera + Five Kingdom · Five Kingdom · Sub-viral agents · Monera and Protista boundary
8 free Biological Classification practice questions with answers
Choose an answer in your head before opening it. Each explanation says why the correct option is right and, where relevant, why the tempting wrong option is wrong.
Question 1 · easy · Five Kingdom Classification
R.H. Whittaker (1969) proposed the five kingdom classification using several criteria. Which one of the following was NOT among the criteria he used?
- A.Mode of nutrition
- B.Habitat of the organism
- C.Cell structure
- D.Phylogenetic relationships
Show answer and explanation
Answer: B. Habitat of the organism
Whittaker used cell structure, body organisation, mode of nutrition, reproduction and phylogenetic relationships as his criteria. Habitat was never a criterion, since organisms of the same kingdom occupy vastly different habitats.
Whittaker's five kingdom classification (Monera, Protista, Fungi, Plantae, Animalia) rests on five main criteria: cell structure (prokaryotic vs eukaryotic), body organisation (unicellular vs multicellular, and the level of tissue organisation), mode of nutrition (autotrophic vs heterotrophic, absorptive vs ingestive), reproduction, and phylogenetic relationships. Habitat cannot serve as a kingdom-level criterion because members of a single kingdom occupy every kind of habitat — bacteria alone live in soil, hot springs, oceans and inside other organisms. Options C and D are genuine Whittaker criteria, so they cannot be the answer to a NOT question.
Common mistake: Marking phylogenetic relationships as the odd one out, thinking evolutionary criteria are a later addition to classification.
Key point: Whittaker's criteria: cell structure, body organisation, mode of nutrition, reproduction, phylogenetic relationships — habitat is not one of them.
Question 2 · easy · Five Kingdom Classification
The earliest scientific classification, given by Linnaeus and used for a long time, grouped all organisms into two kingdoms named:
- A.Plantae and Animalia
- B.Monera and Protista
- C.Prokaryota and Eukaryota
- D.Cryptogamae and Phanerogamae
Show answer and explanation
Answer: A. Plantae and Animalia
Linnaeus's two kingdom system classified every organism as either a plant (kingdom Plantae) or an animal (kingdom Animalia).
Linnaeus proposed the two kingdom system with kingdoms Plantae and Animalia, covering all plants and animals respectively. This system was used for a long time before its inadequacies became clear. It could not distinguish prokaryotes from eukaryotes, unicellular from multicellular organisms, or photosynthetic organisms from non-photosynthetic ones. Monera and Protista (option B) are kingdoms of the later five kingdom scheme. Prokaryota/Eukaryota (option C) is a cell-structure dichotomy, not Linnaeus's classification. Cryptogamae and Phanerogamae (option D) are old subdivisions within plants based on visible reproductive structures, not a classification of all life.
Common mistake: Choosing Cryptogamae and Phanerogamae, which divide only plants, not all organisms.
Key point: Linnaeus's two kingdoms were Plantae and Animalia; all later systems arose from this system's inadequacies.
Question 3 · easy · Five Kingdom Classification
In Whittaker's scheme, single-celled organisms whose cells possess a well-defined nucleus are assigned to the kingdom:
- A.Monera
- B.Fungi
- C.Plantae
- D.Protista
Show answer and explanation
Answer: D. Protista
Kingdom Protista comprises unicellular eukaryotes — single-celled organisms with a well-defined, membrane-bound nucleus.
Whittaker's classification separates unicellular organisms by cell structure: prokaryotic unicells (no nuclear membrane) go to Monera, while eukaryotic unicells (well-defined nucleus with nuclear membrane) form kingdom Protista. Fungi, Plantae and Animalia are eukaryotic but essentially multicellular kingdoms (yeast is a unicellular exception retained in Fungi because of its fungal wall, nutrition and reproduction, not because unicellularity defines the kingdom). Older systems did dump unicellular algae into Plantae, which is exactly the confusion the five kingdom system removed by creating Protista.
Common mistake: Placing all single-celled organisms, including bacteria, in Protista.
Key point: Unicellular + prokaryotic = Monera; unicellular + eukaryotic = Protista.
Question 4 · easy · Five Kingdom Classification
Cyanobacteria photosynthesise just like green plants, yet Whittaker placed them in Monera and not in Plantae. The best justification for this placement is that:
- A.Cyanobacteria are aquatic while plants are terrestrial
- B.Cyanobacteria reproduce sexually while plants do not
- C.Cyanobacteria are prokaryotic, and cell structure takes precedence over mode of nutrition at kingdom level
- D.Cyanobacteria lack chlorophyll and use only accessory pigments
Show answer and explanation
Answer: C. Cyanobacteria are prokaryotic, and cell structure takes precedence over mode of nutrition at kingdom level
All prokaryotes, whatever their nutrition, are placed in Monera. Cyanobacteria lack a membrane-bound nucleus and organelles, so cell structure — the primary criterion — overrides their plant-like photosynthetic nutrition.
The five kingdom system applies its criteria in a logical order, and cell structure comes first: every prokaryote belongs to Monera regardless of whether it is photosynthetic (cyanobacteria), chemosynthetic or heterotrophic. Cyanobacteria have chlorophyll a comparable to that of green plants, so option D is factually wrong. Option A fails because habitat is not a classification criterion, and many plants are aquatic anyway. Option B is backwards — prokaryotes do not show true sexual reproduction, while plants do. This question is the classic illustration that nutrition alone cannot decide kingdom placement.
Common mistake: Assuming any photosynthetic organism must be a plant.
Key point: Prokaryotic cell structure puts an organism in Monera no matter how plant-like its nutrition is.
Question 5 · easy · Five Kingdom Classification
Consider the two statements about Whittaker's classification. Statement I: All prokaryotic organisms are placed in kingdom Monera. Statement II: All eukaryotic organisms are placed in kingdom Protista. Choose the correct option.
- A.Statement I is correct but Statement II is incorrect
- B.Statement I is incorrect but Statement II is correct
- C.Both statements are correct
- D.Both statements are incorrect
Show answer and explanation
Answer: A. Statement I is correct but Statement II is incorrect
Monera contains every prokaryote — eubacteria, cyanobacteria, archaebacteria and mycoplasma. But eukaryotes are spread over four kingdoms (Protista, Fungi, Plantae, Animalia), so Statement II is wrong.
Statement I is true: the defining feature of Monera is the prokaryotic cell, so all bacteria including archaebacteria, cyanobacteria and the wall-less mycoplasma belong there. Statement II is false: Protista holds only the unicellular eukaryotes; multicellular eukaryotes are distributed among Fungi, Plantae and Animalia based on nutrition, wall composition and body organisation. The trap is reading 'eukaryotic' and jumping to Protista without noticing the word 'all'.
Common mistake: Treating Protista as the kingdom of all eukaryotes rather than only unicellular eukaryotes.
Key point: One kingdom for all prokaryotes (Monera); four kingdoms share the eukaryotes.
Question 6 · medium · Five Kingdom Classification
A cell wall made of a noncellulosic polysaccharide combined with amino acid is characteristic of which kingdom in Whittaker's comparison of the five kingdoms?
- A.Fungi
- B.Monera
- C.Plantae
- D.Protista
Show answer and explanation
Answer: B. Monera
In the five kingdom comparison, the moneran cell wall is described as noncellulosic — a polysaccharide plus amino acid (the peptidoglycan type). Fungal walls contain chitin and plant walls contain cellulose.
Whittaker's kingdom-wise comparison assigns each walled kingdom a distinct wall chemistry: Monera — noncellulosic polysaccharide + amino acid (cell wall present in most, absent in mycoplasma); Fungi — chitin; Plantae — cellulose; Protista — wall present in some members (e.g., the siliceous frustule of diatoms) and absent in others; Animalia — wall absent. The 'amino acid' clue is decisive: only the bacterial wall combines sugar polymers with amino acids. This wall chemistry row is one of the most frequently tested comparisons of the chapter.
Common mistake: Assigning the amino-acid-containing wall to Fungi because both fungal and bacterial walls are 'noncellulosic'.
Key point: Wall chemistry: Monera = polysaccharide + amino acid; Fungi = chitin; Plantae = cellulose; Animalia = none.
Question 7 · medium · Five Kingdom Classification
The two kingdom classification was eventually found inadequate and replaced. The core inadequacy was that it:
- A.Was based on evolutionary relationships that later proved wrong
- B.Included viruses within the kingdom Plantae
- C.Did not distinguish prokaryotes from eukaryotes, unicellular from multicellular, or photosynthetic from non-photosynthetic organisms
- D.Created too many kingdoms for convenient study
Show answer and explanation
Answer: C. Did not distinguish prokaryotes from eukaryotes, unicellular from multicellular, or photosynthetic from non-photosynthetic organisms
Lumping all organisms into just plants and animals ignored the fundamental differences between prokaryotes and eukaryotes, unicellular and multicellular forms, and photosynthetic and non-photosynthetic organisms.
Under the two kingdom system, bacteria, cyanobacteria, fungi, algae, mosses and flowering plants all sat together in Plantae simply because they had walls or seemed plant-like. This grouped prokaryotes with eukaryotes, unicells with multicellular organisms, and heterotrophic fungi with photoautotrophic trees — organisms with hardly any fundamental characters in common. The system also was not framed on phylogeny (so option A is wrong), and its fault was too few categories, not too many (option D inverted). The felt need for finer distinctions led to classification systems that culminated in Whittaker's five kingdoms.
Common mistake: Thinking older systems were phylogenetic and merely got the phylogeny wrong.
Key point: Two kingdoms failed on three axes: cell type, cellularity and mode of nutrition.
Question 8 · medium · Five Kingdom Classification
Read the statements regarding the classification of fungi. Statement I: Fungi are heterotrophic organisms showing saprophytic or parasitic modes of nutrition. Statement II: In the two kingdom system, fungi were nevertheless grouped with plants, chiefly because they possess a cell wall. Select the correct option.
- A.Statement I is correct; Statement II is incorrect
- B.Statement I is incorrect; Statement II is correct
- C.Both statements are incorrect
- D.Both statements are correct
Show answer and explanation
Answer: D. Both statements are correct
Fungi lack chlorophyll and live as saprophytes or parasites (Statement I true). The old two kingdom system still filed them under Plantae because, like plants, they have cell walls and are non-motile (Statement II true).
No fungus photosynthesises; nutrition is heterotrophic — saprophytic (on dead substrates) or parasitic (on living hosts), with some living as symbionts in lichens and mycorrhizae. Despite this fundamentally animal-like dependence on ready-made organic food, Linnaeus's system kept fungi in Plantae because superficial characters — a rigid cell wall and lack of locomotion — resembled plants. This mismatch between nutrition and placement was a major argument for giving fungi their own kingdom in Whittaker's scheme, where wall chemistry (chitin) and absorptive nutrition define them.
Common mistake: Assuming any organism with a cell wall must photosynthesise.
Key point: Fungi were once 'plants' only because of their cell wall and immobility; their heterotrophy earned them a separate kingdom.
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Questions about Biological Classification for NEET
How many NEET questions does NEET720 have on Biological Classification?＋
NEET720 has 546 reviewed practice questions on Biological Classification (Botany): 94 easy, 377 medium and 75 hard. 8 of them are free on this page with full explanations; the rest are available in the app.
Is Biological Classification a Class 11 or Class 12 chapter for NEET?＋
Biological Classification is a Class 11 Botany chapter in the NEET (UG) syllabus. Read the NCERT chapter first, then practise chapter-wise MCQs and previous-year questions.
How should I practise Biological Classification for NEET?＋
Attempt the questions below without looking at the options for more than a few seconds, mark your answer, then read the explanation even when you were right. Record every mistake and revisit it after a gap. On NEET720 this happens automatically: wrong answers go to your Mistake Book and are scheduled for spaced revision.
More Botany chapters
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Questions are original NEET720 compositions reviewed for correctness, syllabus fit and option quality. Counts update as the bank grows (546 active practice questions in this chapter today).