Statement — A UN report reviewing the ozone layer since the Montreal Protocol (1987) reveals that the ozone hole over Antarctica is shrinking.\nQuestion — Which conclusion necessarily follows from the statement?

Difficulty: Medium

Correct Answer: if only conclusion II follows

Explanation:


Introduction / Context:
The stem states an observed environmental trend: the Antarctic ozone hole is shrinking. Two conclusions are offered about chlorofluorocarbons (CFCs): (I) removal now exceeds new releases; (II) atmospheric levels of destructive CFCs are declining. We must identify the inference supported by the report without adding stronger claims.



Given Data / Assumptions:


  • Ozone hole size is decreasing.
  • Context references the Montreal Protocol aimed at reducing CFCs.


Concept / Approach:
A shrinking hole is consistent with falling concentrations of ozone-depleting substances (ODS) like CFCs. However, claiming that natural/atmospheric removal outpaces total releases (I) is a stronger, quantitative dynamic not stated in the stem.



Step-by-Step Solution:


Conclusion II (declining ODS levels) aligns with the expected mechanism behind the observed healing and fits the report’s implication.Conclusion I introduces a precise inequality (removal > release) that the stem does not assert; it may be true, but it is not a necessary consequence.


Verification / Alternative check:
The hole could shrink due to lower emissions plus slow stratospheric cleansing; we are not told the current balance is removal > release in all regions/times. Thus II, not I, follows.



Why Other Options Are Wrong:


Any option selecting I overstates the data. “Either” or “neither” misreads the stem’s environmental directionality.


Common Pitfalls:
Conflating “improving indicator” with a specific quantitative mechanistic claim.



Final Answer:
if only conclusion II follows

More Questions from Statement and Conclusion

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