CBSE Class 12 Biology Compartment Question Paper 2025 Set 3 57 S 3

CBSE CLASS XII Questions

• 1.

  Assertion (A) : Hardy-Weinberg principle says that allele frequencies in a population are stable.

  Reason (R) : Hardy-Weinberg principle is applicable only when genetic drift does not occur.

  • Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
  • Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
  • Assertion (A) is true, but Reason (R) is false.
  • Assertion (A) is false, but Reason (R) is true.
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• 2.

  Assertion (A): The embryo with 8 to 16 blastomeres is called a morula.
  Reason (R): The morula continues to divide and transform into trophoblast.
  

  • Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    
  • Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    
  • Assertion (A) is true, but Reason (R) is false.
    
  • Assertion (A) is false, but Reason (R) is true.
    
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• 3.

  A student performed some crosses in plants and represented the result in the form of bar graphs as shown below. Each graph displays the phenotypic proportion of the progeny. Study the graphs and answer the questions :

  

  (c) What conclusion can you draw from the results of bar graphs of crosses I and II ? Name the genetic principle illustrated.

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• 4.

  (i) Differentiate between a DNA and RNA nucleotide.

  (ii) Name the two types of bonds present within a single nucleotide.

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• 5.

  Assertion (A) : The milk produced by transgenic cow 'Rosie' was nutritionally more balanced product for human babies than natural cow milk.
  Reason (R) : It was human protein enriched milk containing human alpha lactaglobulin.
  

  • Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    
  • Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    
  • Assertion (A) is true, but Reason (R) is false.
    
  • Assertion (A) is false, but Reason (R) is true.
    
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• 6.

  Choose a correct option that shows an interaction in which one species benefits while the other is neither harmed nor benefitted.

  • Mycorrhizal associations between fungi and roots of higher plants
    
  • Sea anemone and clownfish
    
  • Abingdon tortoises and goats in the Galapagos Island
    
  • Cuscuta on hedge plants
    
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