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CSS MCQs

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31
Biology Medium

Which chromosomal disorder is caused by the presence of an extra chromosome 21?

  • ATurner syndrome
  • BDown syndrome
  • CKlinefelter syndrome
  • DPatau syndrome
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Correct Answer: Option B — Down syndrome
Explanation: Down syndrome also called trisomy 21 is caused by the presence of an extra copy of chromosome 21 resulting in intellectual disability and characteristic physical features.
Submitted by: PaperMCQs
32
Biology Hard

What is the term for the complete set of chromosomes in a cell of an organism?

  • AGenome
  • BKaryotype
  • CPhenotype
  • DGenotype
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Correct Answer: Option B — Karyotype
Explanation: A karyotype is the complete set of chromosomes in a cell of an organism arranged and displayed in homologous pairs and used to diagnose chromosomal disorders.
Submitted by: PaperMCQs
33
Biology Medium

Which type of RNA brings amino acids to the ribosome during protein synthesis?

  • AmRNA
  • BrRNA
  • CtRNA
  • DsnRNA
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Correct Answer: Option C — tRNA
Explanation: Transfer RNA or tRNA is responsible for bringing specific amino acids to the ribosome during translation each tRNA has an anticodon that matches a codon on the mRNA.
Submitted by: PaperMCQs
34
Biology Hard

What is the process by which organisms survive extreme heat and drought by entering a dormant state?

  • AAestivation
  • BHibernation
  • CMigration
  • DDormancy only
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Correct Answer: Option A — Aestivation
Explanation: Aestivation is a state of dormancy similar to hibernation but entered during hot and dry summer conditions by animals like lungfish snails and some amphibians to prevent dehydration.
Submitted by: PaperMCQs
35
Biology Hard

What is the broadest level of biological classification?

  • ADomain
  • BOrder
  • CFamily
  • DKingdom
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Correct Answer: Option A — Domain
Explanation: Domain is the broadest level in the modern biological classification system above kingdom and includes three domains Bacteria Archaea and Eukarya.
Submitted by: PaperMCQs
36
Biology Medium

What is the two-part Latin naming system for organisms called?

  • APhylogenetic classification
  • BBinomial nomenclature
  • CCladistics
  • DLinnaean classification
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Correct Answer: Option B — Binomial nomenclature
Explanation: Binomial nomenclature is the formal system of naming organisms using two Latin words the genus name and the species name developed by Carl Linnaeus in the 18th century.
Submitted by: PaperMCQs
37
Biology Medium

What is the term for the gradual process of change in the species composition of an ecosystem over time?

  • AEvolution
  • BAdaptation
  • CMigration
  • DEcological succession
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Correct Answer: Option D — Ecological succession
Explanation: Ecological succession is the gradual and predictable process of change in species composition and community structure in an ecosystem over time toward a stable climax community.
Submitted by: PaperMCQs
38
Biology Hard

Which type of ecological succession begins on bare rock or sand where no soil exists?

  • ASecondary succession
  • BAllogenic succession
  • CBiotic succession
  • DPrimary succession
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Correct Answer: Option D — Primary succession
Explanation: Primary succession occurs on bare substrates like bare rock lava fields or sand dunes where no soil or previous living community exists starting from pioneer species like lichens.
Submitted by: PaperMCQs
39
Biology Medium

What is the term for the variety of different species present in a given habitat?

  • AGenetic diversity
  • BSpecies diversity
  • CEcosystem diversity
  • DBiodiversity
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Correct Answer: Option B — Species diversity
Explanation: Species diversity refers to the number and relative abundance of different species present in a given habitat and is an important measure of the biodiversity of an ecosystem.
Submitted by: PaperMCQs
40
Biology Medium

What is the function of lysosomes in animal cells?

  • AProtein synthesis
  • BDigestion of waste materials and cellular debris
  • CEnergy production
  • DDNA storage
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Correct Answer: Option B — Digestion of waste materials and cellular debris
Explanation: Lysosomes are membrane-bound organelles containing digestive enzymes that break down waste materials damaged organelles and foreign substances through a process called autophagy.
Submitted by: PaperMCQs
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