CAT 2025 Slot 3 VARC Question & Solution
Question
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)____.
Options
Solution
Main Idea of the Paragraph
The paragraph describes the first evidence of a genetic mutation linked to aggressive behaviour in humans. It follows a clear scientific progression:
- Introduction of the study
- Description of the affected group
- Explanation of their abnormal behaviour
- Identification of the genetic basis of this behaviour, moving from general location to a specific mutation
Explanation of the Correct Answer
Why the Sentence Fits Best at Blank (3)
The given sentence states:
“In each of the affected males, the genetic defect was located to the X chromosome in the region of p11–12.”
This sentence fits best at blank (3) because of the logical flow of ideas:
-
Before blank (3), the paragraph:
- Introduces the Dutch family
- Describes the undesirable behaviours (impulsive aggression, arson, exhibitionism)
-
The given sentence naturally follows this by:
- Shifting from behavioral description to genetic explanation
- Providing a general location of the genetic defect
-
The sentence after blank (3):
- Identifies a specific point mutation in the MAOA gene
- This works as a more detailed follow-up to the chromosome-level location
Thus, blank (3) acts as a bridge between observed behaviour and precise genetic findings.
Why the Other Blanks Do Not Work
-
Blank (1):
- Comes too early
- The affected individuals and family have not yet been introduced
-
Blank (2):
- Appears immediately after introducing the family
- At this stage, the paragraph is still setting context, not yet moving to genetic conclusions
-
Blank (4):
- Comes after the specific MAOA mutation is already identified
- The chromosome-level location would feel redundant and backward here