Passage: Scientists studied the vernal window transition period from winter to the growing season. They…
Passage: 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 time 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.
Question: 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?
1 only
2 only
Both 1 and 2
Neither 1 nor 2
Solution
Assumption 1 is valid — warmer winters (linked to global warming) lengthen the vernal window, implying spring comes early and lasts longer. Assumption 2 is not supported; the passage notes birds don't return when ice melts early, but does not claim early/longer spring is generally bad for bird populations. Only assumption 1 is correct.