NEET 2025 MCQ with Answer Explanation : “Biological Classification”.

51. Which of the following is an example of a photosynthetic protist?
    a) Paramecium
    b) Euglena
    c) Amoeba
    d) Plasmodium

Answer: b) Euglena

Explanation:
Euglena is a protist that can photosynthesize due to the presence of chloroplasts, though it can also obtain nutrients heterotrophically when light is unavailable.

52. Which group of organisms is often referred to as the ‘pioneer colonizers’ of bare rock?
    a) Algae
    b) Fungi
    c) Lichens
    d) Mosses

Answer: c) Lichens

Explanation:
Lichens are symbiotic associations between fungi and algae or cyanobacteria and are often the first organisms to colonize bare rock surfaces, initiating soil formation.

53. Which of the following is an example of a nitrogen-fixing bacterium?
    a) Escherichia coli
    b) Rhizobium
    c) Mycobacterium
    d) Vibrio cholerae

Answer: b) Rhizobium

Explanation:
Rhizobium is a nitrogen-fixing bacterium that forms symbiotic relationships with leguminous plants, converting atmospheric nitrogen into ammonia.

54. In viruses, the protein coat surrounding the nucleic acid is known as:
    a) Envelope
    b) Capsid
    c) Pili
    d) Plasmid

Answer: b) Capsid

Explanation:
The capsid is the protein shell that encloses the genetic material of a virus, providing protection and aiding in the virus’s ability to infect host cells.

55. Which of the following is a fungal disease?
    a) Cholera
    b) Typhoid
    c) Ringworm
    d) Tuberculosis

Answer: c) Ringworm

Explanation:
Ringworm is a fungal infection caused by dermatophytes, which affect the skin, hair, and nails.

56. Which of the following organisms has a prokaryotic cell structure?
    a) Amoeba
    b) Fungi
    c) Cyanobacteria
    d) Algae

Answer: c) Cyanobacteria

Explanation:
Cyanobacteria are prokaryotic organisms, meaning they lack a true nucleus and membrane-bound organelles. They are capable of photosynthesis.

57. Which of the following features is found in all prokaryotes?
    a) Mitochondria
    b) Nucleus
    c) 70S ribosomes
    d) Endoplasmic reticulum

Answer: c) 70S ribosomes

Explanation:
Prokaryotic cells, such as bacteria, have 70S ribosomes for protein synthesis, but they lack membrane-bound organelles like mitochondria and a nucleus.

58. Which of the following is an example of a eukaryotic organism?
    a) Bacteria
    b) Mycoplasma
    c) Paramecium
    d) Archaebacteria

Answer: c) Paramecium

Explanation:
Paramecium is a unicellular eukaryotic organism found in the kingdom Protista. It has a true nucleus and membrane-bound organelles.

59. Which of the following kingdoms contains organisms that are exclusively heterotrophic?
    a) Plantae
    b) Fungi
    c) Protista
    d) Monera

Answer: b) Fungi

Explanation:
The kingdom Fungi consists of organisms that are heterotrophic, meaning they obtain their food by absorbing nutrients from dead or decaying organic matter or living hosts.

60. Which of the following is not a characteristic of Archaebacteria?
    a) Presence of a peptidoglycan cell wall
    b) Ability to live in extreme environments
    c) Lack of true nucleus
    d) Presence of unique lipids in the cell membrane

Answer: a) Presence of a peptidoglycan cell wall

Explanation:
Archaebacteria have cell walls that lack peptidoglycan, which is found in eubacteria. Instead, they have unique cell wall components like pseudopeptidoglycan.