Chapter 2: Biological Classification – MCQs
🧬 Biological Classification – MCQs
Part 1 (Q1–Q25)
Q1. Who proposed the two-kingdom system of classification?
A) Whittaker
B) Aristotle
C) Linnaeus ✅
D) Haeckel
Explanation: Linnaeus classified living organisms into two kingdoms – Plantae and Animalia.
Q2. Which of the following is not included in Monera?
A) Bacteria
B) Cyanobacteria
C) Mycoplasma
D) Amoeba ✅
Explanation: Amoeba belongs to Protista, not Monera.
Q3. Five-kingdom classification was given by:
A) Linnaeus
B) Whittaker ✅
C) Haeckel
D) Copeland
Explanation: R.H. Whittaker (1969) proposed the Five-Kingdom classification – Monera, Protista, Fungi, Plantae, Animalia.
Q4. Which of the following is a prokaryote?
A) Amoeba
B) Paramecium
C) Bacterium ✅
D) Euglena
Explanation: Bacteria lack a true nucleus, so they are prokaryotes.
Q5. Which organism is considered a connecting link between plants and animals?
A) Euglena ✅
B) Paramecium
C) Hydra
D) Volvox
Explanation: Euglena has plant-like (photosynthesis) and animal-like (movement) features.
Q6. Kingdom Monera includes:
A) Bacteria only
B) Bacteria, Cyanobacteria, Mycoplasma ✅
C) Bacteria and Algae
D) Fungi
Explanation: Monera includes all prokaryotes – bacteria, blue-green algae (cyanobacteria), and mycoplasma.
Q7. Which kingdom includes unicellular eukaryotes?
A) Protista ✅
B) Monera
C) Plantae
D) Fungi
Explanation: Protista includes unicellular eukaryotes like Amoeba, Paramecium, Euglena.
Q8. Viruses are placed in classification as:
A) Monera
B) Protista
C) Fungi
D) Not included ✅
Explanation: Viruses are acellular, hence excluded from Whittaker’s system.
Q9. Which is the smallest living organism?
A) Bacterium
B) Virus
C) Mycoplasma ✅
D) Algae
Explanation: Mycoplasma is the smallest free-living organism without a cell wall.
Q10. Methanogens are found in:
A) Human intestine
B) Salty water
C) Hot springs
D) Rumen of cattle ✅
Explanation: Methanogenic archaebacteria live in cattle rumen and produce methane gas.
Q11. Blue-green algae are also called:
A) Green algae
B) Cyanobacteria ✅
C) Diatoms
D) Mycoplasma
Explanation: Cyanobacteria are also known as blue-green algae.
Q12. Which is called “producer of antibiotics”?
A) Yeast
B) Penicillium ✅
C) Nostoc
D) Rhizobium
Explanation: Penicillium notatum produces penicillin (antibiotic).
Q13. Which kingdom includes slime molds?
A) Fungi
B) Protista ✅
C) Plantae
D) Monera
Explanation: Slime molds belong to Protista, showing both fungal and amoeboid features.
Q14. The mode of nutrition in fungi is:
A) Autotrophic
B) Saprophytic ✅
C) Parasitic
D) Photosynthetic
Explanation: Fungi are heterotrophic absorptive (saprophytes).
Q15. Cell wall of fungi is made up of:
A) Cellulose
B) Chitin ✅
C) Peptidoglycan
D) Protein
Explanation: Fungal cell walls contain chitin, not cellulose.
Q16. Which is a unicellular fungus?
A) Rhizopus
B) Penicillium
C) Yeast ✅
D) Aspergillus
Explanation: Yeast is unicellular, while others are multicellular.
Q17. Which group is called “amphibians of plant kingdom”?
A) Algae
B) Bryophytes ✅
C) Pteridophytes
D) Gymnosperms
Explanation: Bryophytes live on land but need water for reproduction.
Q18. The dominant phase in bryophytes is:
A) Sporophyte
B) Gametophyte ✅
C) Both equal
D) None
Explanation: In bryophytes, gametophyte is dominant and independent.
Q19. Pteridophytes reproduce by:
A) Seeds
B) Spores ✅
C) Fruits
D) Gametes
Explanation: Pteridophytes are seedless vascular plants, reproducing by spores.
Q20. Gymnosperms produce seeds but lack:
A) Pollen grains
B) Ovules
C) Flowers ✅
D) Roots
Explanation: Gymnosperms bear naked seeds, without flowers and fruits.
Q21. Which is an example of angiosperms?
A) Cycas
B) Pinus
C) Mango ✅
D) Fern
Explanation: Mango is a flowering plant (angiosperm).
Q22. Binomial nomenclature was introduced by:
A) Darwin
B) Haeckel
C) Linnaeus ✅
D) Aristotle
Explanation: Carl Linnaeus introduced binomial nomenclature (Genus + Species).
Q23. Which of the following belongs to Archaebacteria?
A) Nostoc
B) Methanogens ✅
C) Mycoplasma
D) Streptococcus
Explanation: Methanogens, halophiles, and thermoacidophiles are archaebacteria.
Q24. Viruses contain:
A) Only DNA
B) Only RNA
C) Either DNA or RNA ✅
D) Both DNA and RNA
Explanation: Viruses contain either DNA or RNA, but never both.
Q25. Diatoms belong to:
A) Cyanobacteria
B) Dinoflagellates
C) Chrysophytes ✅
D) Fungi
Explanation: Diatoms are golden algae, belonging to Chrysophyta (Protista).
🧬 Diversity of the Living World – Biological Classification
Part 2 (Q26–Q50)
Q26. Which pigment is present in cyanobacteria?
A) Chlorophyll-a ✅
B) Chlorophyll-b
C) Phycoerythrin
D) Carotene
Explanation: Cyanobacteria contain chlorophyll-a like higher plants, hence photosynthetic.
Q27. The reserve food material in fungi is:
A) Starch
B) Glycogen ✅
C) Cellulose
D) Oil
Explanation: Like animals, fungi store glycogen as reserve food.
Q28. Which group of plants is called vascular cryptogams?
A) Bryophytes
B) Pteridophytes ✅
C) Gymnosperms
D) Angiosperms
Explanation: Pteridophytes have vascular tissues but reproduce by spores (cryptogams).
Q29. Which of the following is a symbiotic association?
A) Mycorrhiza ✅
B) Bacteriophage
C) Lichen ✅
D) Both A & C
Answer: D) Both A & C
Explanation: Mycorrhiza (fungus + roots) and Lichen (fungus + algae/cyanobacteria) are symbiotic.
Q30. Which fungi are known as imperfect fungi?
A) Basidiomycota
B) Deuteromycota ✅
C) Zygomycota
D) Ascomycota
Explanation: Deuteromycota are called imperfect fungi as their sexual stage is absent.
Q31. Sexual reproduction in fungi involves:
A) Karyogamy and meiosis ✅
B) Mitosis only
C) Cytokinesis only
D) Budding
Explanation: In fungi, sexual cycle involves plasmogamy → karyogamy → meiosis.
Q32. Which of the following is a prokaryotic autotroph?
A) Nostoc ✅
B) Yeast
C) Amoeba
D) Hydra
Explanation: Nostoc (cyanobacterium) is a prokaryote that performs photosynthesis.
Q33. Which is the characteristic feature of Archaebacteria?
A) Cell wall without peptidoglycan ✅
B) Cell wall with peptidoglycan
C) Presence of nucleus
D) Absence of RNA
Explanation: Archaebacteria cell wall lacks peptidoglycan and has unique lipids.
Q34. Dinoflagellates usually have:
A) One flagellum
B) Two flagella ✅
C) No flagella
D) Cilia
Explanation: Dinoflagellates have two flagella placed in grooves.
Q35. Red tide in sea water is caused by:
A) Cyanobacteria
B) Dinoflagellates ✅
C) Diatoms
D) Fungi
Explanation: Some dinoflagellates (e.g., Gonyaulax) cause red tides due to population explosion.
Q36. Which of the following has a silica cell wall?
A) Cyanobacteria
B) Diatoms ✅
C) Dinoflagellates
D) Mycoplasma
Explanation: Diatoms have a cell wall impregnated with silica, called frustule.
Q37. The term “taxonomy” was coined by:
A) Aristotle
B) Linnaeus
C) A.P. de Candolle ✅
D) Theophrastus
Explanation: A.P. de Candolle (1813) introduced the term taxonomy.
Q38. Which of the following is a nitrogen-fixing bacterium in root nodules of legumes?
A) Azotobacter
B) Rhizobium ✅
C) Nostoc
D) Mycobacterium
Explanation: Rhizobium forms root nodules in legumes and fixes nitrogen.
Q39. Which one is called “golden algae”?
A) Diatoms ✅
B) Cyanobacteria
C) Dinoflagellates
D) Rhizopus
Explanation: Diatoms are also called golden algae (chrysophytes).
Q40. Mycoplasma are unique because:
A) They have no DNA
B) They lack a cell wall ✅
C) They are multicellular
D) They are autotrophic
Explanation: Mycoplasma are the smallest, wall-less, free-living prokaryotes.
Q41. Which kingdom includes prokaryotic organisms only?
A) Monera ✅
B) Protista
C) Fungi
D) Plantae
Explanation: Kingdom Monera contains only prokaryotes (bacteria, cyanobacteria, mycoplasma).
Q42. Algal blooms are caused due to:
A) Excess nutrients ✅
B) Lack of sunlight
C) Viral infection
D) Fungal infection
Explanation: Nutrient-rich water leads to algal blooms, reducing oxygen levels.
Q43. The term “systematics” was given by:
A) Theophrastus
B) Carolus Linnaeus
C) Gaspard Bauhin
D) Linnaeus ✅
Explanation: Linnaeus introduced the term systematics for classification and nomenclature.
Q44. Which of the following are saprophytes?
A) Yeast
B) Rhizopus ✅
C) Nostoc
D) Euglena
Explanation: Rhizopus (bread mold) feeds on dead organic matter.
Q45. Kingdom Protista includes:
A) Only autotrophs
B) Only heterotrophs
C) Both autotrophs and heterotrophs ✅
D) Only parasites
Explanation: Protists may be autotrophic (Euglena) or heterotrophic (Amoeba, Paramecium).
Q46. Which is the first step in scientific classification?
A) Kingdom
B) Species ✅
C) Genus
D) Order
Explanation: Species is the basic unit of classification.
Q47. Which is an example of basidiomycetes?
A) Rhizopus
B) Mushroom ✅
C) Yeast
D) Neurospora
Explanation: Mushroom, puffballs, smuts belong to Basidiomycetes.
Q48. The largest number of organisms belong to which group?
A) Fungi
B) Monera ✅
C) Plantae
D) Animalia
Explanation: Bacteria (Monera) are the most abundant and diverse organisms.
Q49. Lichens are sensitive to:
A) Water pollution
B) Soil pollution
C) Air pollution ✅
D) Noise pollution
Explanation: Lichens are bioindicators of air pollution, especially SO₂.
Q50. The main basis of Whittaker’s classification was:
A) Structure of nucleus
B) Cell structure, nutrition, reproduction ✅
C) DNA structure
D) Number of chromosomes
Explanation: Whittaker classified organisms based on cell structure, mode of nutrition, and reproduction.
🧬 Diversity of the Living World – Biological Classification
Part 3 (Q51–Q75)
Q51. Which group of fungi forms symbiotic association with algae?
A) Basidiomycota
B) Ascomycota
C) Lichens ✅
D) Deuteromycota
Explanation: Lichens are a symbiotic association of fungus (Ascomycota/Basidiomycota) and algae/cyanobacteria.
Q52. In which kingdom are multicellular, eukaryotic, autotrophs placed?
A) Protista
B) Plantae ✅
C) Fungi
D) Animalia
Explanation: Plantae includes multicellular autotrophic eukaryotes.
Q53. The bread mold is:
A) Rhizopus ✅
B) Aspergillus
C) Penicillium
D) Saccharomyces
Explanation: Rhizopus stolonifer is the common bread mold.
Q54. Which protist moves with cilia?
A) Amoeba
B) Euglena
C) Paramecium ✅
D) Plasmodium
Explanation: Paramecium moves with cilia and is also called ciliate.
Q55. Plasmodium, the malarial parasite, belongs to:
A) Ciliates
B) Flagellates
C) Sporozoans ✅
D) Amoeboids
Explanation: Plasmodium is an apicomplexan protozoan (sporozoan).
Q56. Which type of reproduction is common in Monera?
A) Sexual
B) Binary fission ✅
C) Budding
D) Fragmentation
Explanation: Bacteria reproduce asexually by binary fission.
Q57. Which plant group shows alternation of generations?
A) Bryophytes ✅
B) Gymnosperms
C) Angiosperms
D) All of the above
Explanation: Alternation of generations is present in all plants, but most clearly studied in bryophytes.
Q58. Which protist causes sleeping sickness?
A) Plasmodium
B) Trypanosoma ✅
C) Amoeba
D) Giardia
Explanation: Trypanosoma brucei, transmitted by tsetse fly, causes sleeping sickness.
Q59. Which is a feature of viruses?
A) Living only outside host
B) Non-cellular, obligate parasites ✅
C) Prokaryotic cells
D) Multicellular
Explanation: Viruses are acellular obligate parasites, living only inside a host.
Q60. The binomial name of wheat is:
A) Oryza sativa
B) Triticum aestivum ✅
C) Zea mays
D) Hordeum vulgare
Explanation: Triticum aestivum is the scientific name of wheat.
Q61. Who is known as the “Father of Taxonomy”?
A) Darwin
B) Aristotle
C) Linnaeus ✅
D) Haeckel
Explanation: Carl Linnaeus is called the Father of Taxonomy.
Q62. Whittaker’s five-kingdom classification does not include:
A) Monera
B) Protista
C) Viruses ✅
D) Fungi
Explanation: Viruses are acellular and excluded from Whittaker’s classification.
Q63. Which of the following is a coenocytic fungus?
A) Rhizopus ✅
B) Yeast
C) Neurospora
D) Penicillium
Explanation: Rhizopus has coenocytic (multinucleated) hyphae.
Q64. Which bacteria convert milk into curd?
A) Rhizobium
B) Lactobacillus ✅
C) Azotobacter
D) Mycobacterium
Explanation: Lactobacillus ferments lactose sugar into lactic acid, forming curd.
Q65. Viroids differ from viruses in:
A) Having DNA only
B) Having RNA only ✅
C) Having both DNA & RNA
D) Being cellular
Explanation: Viroids are infectious agents with naked RNA only, lacking protein coat.
Q66. Which protist causes amoebic dysentery?
A) Amoeba proteus
B) Entamoeba histolytica ✅
C) Plasmodium
D) Giardia
Explanation: Entamoeba histolytica causes amoebic dysentery in humans.
Q67. Which bacteria are used in sewage treatment?
A) Fungi
B) Methanogens ✅
C) Cyanobacteria
D) Yeast
Explanation: Methanogens break down organic matter in sewage and produce biogas.
Q68. Kingdom Plantae excludes:
A) Mosses
B) Ferns
C) Bacteria ✅
D) Gymnosperms
Explanation: Bacteria belong to Monera, not Plantae.
Q69. Which is a free-living nitrogen fixer?
A) Lactobacillus
B) Azotobacter ✅
C) Rhizobium
D) Mycoplasma
Explanation: Azotobacter is a free-living nitrogen-fixing bacterium.
Q70. Which of the following organisms lacks chlorophyll?
A) Euglena
B) Spirogyra
C) Mushroom ✅
D) Nostoc
Explanation: Fungi (mushrooms) lack chlorophyll and are heterotrophic.
Q71. In which group do you find pseudopodia?
A) Ciliates
B) Flagellates
C) Amoeboids ✅
D) Sporozoans
Explanation: Amoeboids (e.g., Amoeba) move using pseudopodia.
Q72. Which fungal group produces motile zoospores?
A) Ascomycota
B) Basidiomycota
C) Zygomycota
D) Phycomycota ✅
Explanation: Phycomycota (lower fungi) produce motile, flagellated zoospores.
Q73. Which of the following is used as a biofertilizer?
A) Nostoc ✅
B) Plasmodium
C) Yeast
D) Rhizopus
Explanation: Cyanobacteria like Nostoc and Anabaena fix nitrogen, used as biofertilizers.
Q74. Which type of nutrition is shown by fungi?
A) Absorptive heterotrophic ✅
B) Photosynthetic
C) Chemosynthetic
D) Saprophytic only
Explanation: Fungi are absorptive heterotrophs, including saprophytes and parasites.
Q75. Which of the following is an example of Ascomycetes?
A) Yeast ✅
B) Mushroom
C) Rhizopus
D) Puccinia
Explanation: Yeast, Neurospora, and Penicillium belong to Ascomycetes (sac fungi).
🧬 Diversity of the Living World – Biological Classification
Part 4 (Q76–Q100)
Q76. Which of the following belongs to Basidiomycetes?
A) Neurospora
B) Mushroom ✅
C) Yeast
D) Rhizopus
Explanation: Mushrooms, puffballs, smuts are examples of Basidiomycetes (club fungi).
Q77. Which fungi are called “sac fungi”?
A) Ascomycetes ✅
B) Basidiomycetes
C) Zygomycetes
D) Deuteromycetes
Explanation: Ascomycetes form sexual spores inside a sac-like structure, ascus.
Q78. Which of the following is an obligate parasite?
A) Yeast
B) Rhizopus
C) Puccinia (rust fungus) ✅
D) Penicillium
Explanation: Puccinia requires a living host to complete its life cycle.
Q79. Which part of algae is used in agar-agar production?
A) Brown algae ✅
B) Red algae
C) Green algae
D) Cyanobacteria
Explanation: Red algae (Gelidium, Gracilaria) are the major sources of agar, used in labs.
(Correction: Red algae → ✅)
Q80. Which algae is used as food in Japan (nori)?
A) Laminaria ✅
B) Spirogyra
C) Ulva
D) Volvox
Explanation: Laminaria and Porphyra (nori) are eaten as seaweeds.
Q81. Gymnosperms are characterized by:
A) Naked seeds ✅
B) Seeds inside fruits
C) No seeds
D) Motile gametes
Explanation: Gymnosperms bear naked seeds, not enclosed in fruits.
Q82. Which group is the most advanced in the plant kingdom?
A) Bryophytes
B) Pteridophytes
C) Gymnosperms
D) Angiosperms ✅
Explanation: Angiosperms are the most advanced, with flowers, fruits, and double fertilization.
Q83. Which one is a non-vascular plant?
A) Moss ✅
B) Fern
C) Cycas
D) Mango
Explanation: Bryophytes (mosses, liverworts) are non-vascular.
Q84. The dominant stage in pteridophytes is:
A) Gametophyte
B) Sporophyte ✅
C) Both equal
D) None
Explanation: In pteridophytes, the sporophyte is dominant and independent.
Q85. The gametophyte in angiosperms is:
A) Diploid
B) Haploid ✅
C) Triploid
D) Polyploid
Explanation: Gametophytes are haploid, formed by meiosis of sporophyte cells.
Q86. Which algae is called kelp?
A) Laminaria ✅
B) Volvox
C) Spirogyra
D) Chlamydomonas
Explanation: Laminaria, a large brown alga, is known as kelp.
Q87. Which plant shows double fertilization?
A) Cycas
B) Pinus
C) Mango ✅
D) Fern
Explanation: Double fertilization is a unique feature of angiosperms (e.g., Mango).
Q88. Which of the following is a heterotrophic protist?
A) Amoeba ✅
B) Spirogyra
C) Volvox
D) Euglena (autotrophic in light)
Explanation: Amoeba feeds by phagocytosis, hence heterotrophic.
Q89. Which of the following is a colonial alga?
A) Spirogyra
B) Volvox ✅
C) Chlamydomonas
D) Ulothrix
Explanation: Volvox is a colonial green alga, forming spherical colonies.
Q90. Cyanobacteria can fix nitrogen in:
A) Heterocysts ✅
B) Rhizoids
C) Root nodules
D) Sporangia
Explanation: Cyanobacteria (e.g., Anabaena, Nostoc) fix nitrogen inside specialized cells called heterocysts.
Q91. Which one is a homosporous plant?
A) Fern ✅
B) Cycas
C) Pinus
D) Mango
Explanation: Ferns produce only one type of spore (homosporous).
Q92. An example of a heterosporous pteridophyte is:
A) Selaginella ✅
B) Fern
C) Lycopodium
D) Psilotum
Explanation: Selaginella produces two types of spores (microspores & megaspores).
Q93. In gymnosperms, the male gametophyte is:
A) Antherozoid
B) Pollen grain ✅
C) Sperm nucleus
D) Zygote
Explanation: In gymnosperms, pollen grains represent male gametophytes.
Q94. Which is the largest algae?
A) Laminaria ✅
B) Spirogyra
C) Chlamydomonas
D) Ulva
Explanation: Brown algae Laminaria (kelp) can grow up to several meters.
Q95. The first land plants were:
A) Pteridophytes
B) Bryophytes ✅
C) Gymnosperms
D) Angiosperms
Explanation: Bryophytes were the first land plants, still dependent on water for fertilization.
Q96. In angiosperms, endosperm is:
A) Diploid
B) Triploid ✅
C) Haploid
D) Polyploid
Explanation: Endosperm is triploid (3n), formed after double fertilization.
Q97. Who proposed the three-domain system?
A) Whittaker
B) Woese ✅
C) Linnaeus
D) Haeckel
Explanation: Carl Woese (1990) proposed three domains – Archaea, Bacteria, Eukarya.
Q98. Which of the following belongs to Zygomycota?
A) Rhizopus ✅
B) Saccharomyces
C) Neurospora
D) Puccinia
Explanation: Rhizopus (bread mold) belongs to Zygomycota (zygomycetes).
Q99. The scientific name of housefly is:
A) Musca domestica ✅
B) Apis indica
C) Drosophila melanogaster
D) Anopheles gambiae
Explanation: Musca domestica is the binomial name of the housefly.
Q100. The main purpose of biological classification is to:
A) Identify organisms
B) Arrange organisms into groups
C) Study evolutionary relationships
D) All of the above ✅
Explanation: Classification helps in identification, grouping, and understanding evolutionary relationships.
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