Which among the following is the most logical corollary to the above passage ?
- (a) Mass nesting in all species of birds is essential to ensure complete survival of their offspring.
- (b) Only birds have the capacity to develop social behaviour and thus can do mass nesting to raise their chicks in safety.
- (c) Social behaviour in some species of birds increases the odds of survival in an unsafe world. ✓ UPSC's answer
- (d) All species of birds set up crèches for their chicks to teach them social behaviour and loyalty.
Why the answer is (c)
• The passage describes flamingos as social and loyal, performing group mating dances, and gathering chicks into crèches specifically 'for protection' while both parents go to find food. A corollary must be a conclusion that follows directly from these stated facts without overgeneralising.
• Option (c) says 'Social behaviour in some species of birds increases the odds of survival in an unsafe world.' The phrase 'some species' is appropriately narrow, since the passage only documents flamingos. The word 'protection' in the passage directly implies an unsafe environment, and the act of gathering chicks into crèches while parents forage is a social behaviour that enhances the chicks' chances of surviving.
• The passage establishes a causal link: because the world is unsafe (hence the need for protection), the social behaviour of crèche-gathering and group activity serves to keep the young alive. This is exactly what (c) states as a logical consequence.
• No other option stays within the bounds of what the passage actually says. (a) and (d) universalise to 'all species of birds,' and (b) claims 'only birds' can develop social behaviour, none of which the passage supports.
• Therefore, (c) is the most logical corollary because it draws the minimal, text-supported inference: social behaviour in at least one bird species (flamingos) functions to improve survival in a threatening environment.
Why the other options are wrong
- (a) Mass nesting in all species of birds is essential to ensure complete survival of their…
- The passage discusses only flamingos, not 'all species of birds,' and it never states that mass nesting is 'essential' or that it ensures 'complete survival'; it merely describes a protective practice in one species.
- (b) Only birds have the capacity to develop social behaviour and thus can do mass nesting to…
- The passage makes no claim that 'only birds' can develop social behaviour; it simply describes flamingo behaviour. Introducing an exclusive 'only birds' assertion goes far beyond anything stated in the passage.
- (d) All species of birds set up crèches for their chicks to teach them social behaviour and…
- The passage limits its description to flamingos, not 'all species of birds,' and it states that crèches are for 'protection,' not to 'teach them social behaviour and loyalty.' Both the universal quantifier and the stated purpose are unsupported.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2015, held on 23 August 2015. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.