CAT 2025 Slot 3 · VARC · Question 23

CAT 2025 Slot 3 previous year question on Sentence Completion and Insertion, with the answer and a step-by-step solution.

Sentence Completion and InsertionVerbal AbilityMultiple choiceMedium

The given sentence is missing in the paragraph below. Decide where it best fits among the options 1, 2, 3, or 4 indicated in the paragraph.

Sentence: In each of the affected males, the genetic defect was located to the X chromosome in the region of p11-12.

Paragraph: The first suggested evidence of a human genetic mutation associated with aggressive behaviour came from a study in 1993. _____(1)____. Genetic and metabolic studies were conducted on a large Dutch family in which several of the males has a syndrome of borderline mental retardation and abnormal behaviour. _____(2)____. The undesirable behaviour included impulsive aggression, arson and exhibitionism. _____(3)____. A point mutation was identified in the eighth exon of the monoamine oxidase A (MAOA) structural gene which changes glutamine to a termination codon. _____(4)____.

  1. A

    Option 2

  2. B

    Option 1

  3. C

    Option 3

  4. D

    Option 4

Pick an option, then check.
Answer & solution

Answer: Option C

The paragraph is a narrowing funnel: a 1993 study, then the Dutch family, then the behaviour observed, then the precise point mutation in the MAOA gene. The missing sentence sits at an intermediate level of precision – the defect localised to a region of the X chromosome, p11-12 – and it refers to 'the affected males'.

Blank 1 comes before the Dutch family has been introduced. 'The affected males' would have no antecedent there, so it is out.

Blank 2 falls between the sentence naming the Dutch family's syndrome of abnormal behaviour and the sentence spelling that behaviour out – impulsive aggression, arson, exhibitionism. Those two belong together; inserting a chromosomal detail between them breaks the description.

Blank 3 is the right slot. The affected males have been introduced and described, so the reference is anchored. The sentence then narrows from behaviour to genetics at the level of a chromosomal region, and hands over to the next sentence, which narrows further to a single point mutation in one exon. Region before point is the correct order of precision.

Blank 4 comes after the point mutation has been identified. Returning to a broad chromosomal region after naming the exact mutation reverses the funnel.

Shortcut: in a scientific paragraph, placement usually follows increasing specificity. Rank the sentences coarse to fine and slot the missing one by its own grain – here, chromosome region sits between behaviour and exon.

The answer is 'Option 3', which is listed third. Hence, the answer is option 3.

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