Comprehension : Comprehension

Q 98 / 466

UPSC CSE Prelims 2023

Scientists studied the vernal window—transition period from winter to the growing season. They found that Warmer winters with less snow resulted in a longer lag tune between spring events and a more protracted vernal window. This change in the spring timetable has ecological, social and economic consequences — for agriculture, fisheries and tourism. As the ice melts earlier, the birds don't return, causing a delay, or lengthening in springtime ecological events.

With reference to the above passage. the following assumptions have been made:

  1. Global warming is causing spring to come early and for longer durations.
  2. Early spring and longer period of spring is not good for bird populations

Which of the above assumptions is/are correct?

EXPLANATION

Correct Option (D)

Neither 1 nor 2

Assumption 1 is not supported by the passage. The text states that "warmer winters with less snow resulted in a longer lag time between spring events and a more protracted vernal window." While a "protracted vernal window" indicates a lengthened transition period, the passage does not explicitly state that spring arrives *earlier* due to global warming. It describes a change in the timing and duration of the transitional phase.

Assumption 2 is also not supported. The passage mentions that "as the ice melts earlier, the birds don't return, causing a delay, or lengthening in springtime ecological events." This indicates a disruption in the synchronicity of ecological events, specifically a delayed return of birds. However, the passage does not explicitly conclude that "early spring and longer period of spring is not good for bird populations." It describes a timing mismatch, not a direct negative impact of an early or prolonged spring on bird populations as a whole.

Incorrect Options:

Option (A) is incorrect because Assumption 1 cannot be directly inferred from the passage. The passage highlights a "longer lag time" and a "protracted vernal window," which refers to a lengthened transition period, not necessarily an earlier onset of spring.

Option (B) is incorrect because Assumption 2 is not explicitly stated or concluded in the passage. The text describes a delay in bird return relative to earlier ice melt, but it does not equate this to "early spring and longer period of spring is not good for bird populations."

Option (C) is incorrect as both Assumption 1 and Assumption 2 are not directly supported by the information provided in the passage.