Researcher: It is widely believed that, given its northerly latitude, England’s mild winters must be due to the Gulf Stream, which brings warm water flowing northeastward across the Atlantic Ocean.
Opposing Idea
It is widely believed that, given its northerly latitude, England’s mild winters must be due to the Gulf Stream, which brings warm water flowing northeastward across the Atlantic Ocean.
Conclusion
This belief is mistaken [in other words, England's mild winters are not due to the Gulf Stream].
Evidence
In the Pacific Ocean the analogous Kuroshio Current brings tropical water only as far north as Oregon. Yet North America’s west coast has mild winters well north of that point.
Evaluate
This argument discusses possible explanations for a curious fact. Why are England's winters so mild?
We don't see a clear conclusion indicator word like "therefore" in this argument, or any clear premise indicator like "because." But the argument follows a familiar pattern. It begins by describing a common belief. The second sentence presents the main conclusion of the argument, which claims that the common belief is incorrect. Everything that follows this second sentence provides support for the conclusion.
The pivot indicator "but" at the beginning of the second sentence helps us see that we're pivoting from the belief described in the first sentence to something different. "But" isn't automatically or always a conclusion indicator, but we do often see the conclusion of the argument immediately after this kind of pivot.
It's also helpful to notice that the second sentence looks like an opinion, while everything else in the argument appears factual. Even the first sentence is factual. would be an opinion, but that's not what the first sentence tells us. The first sentence states that this idea about England's winter is "widely believed," which is presented as a statement of fact.
If most of the statements in an argument seem factual, and one seems like an opinion, the opinion is probably the conclusion.
Goal
Look for an answer which states that the Gulf Stream is not the cause of England's mild winters. Beware of answers which describe other parts of the argument, like premises or the opposing idea.