Historians analyzing the decline of ancient Silk Road trading oases have traditionally held that the emergence of maritime trade routes rendered overland silk transport economically obsolete. However, recent tree-ring data from timbers used in oasis fortresses indicates that structural maintenance of these outposts continued unabated for over a century after maritime routes were fully established. Furthermore, records of regional toll collection demonstrate that overland traffic volume remained stable until a series of severe desiccation events dried up local glacial tributaries. The loss of local water supplies deprived these oases of the agricultural self-sufficiency required to resupply passing caravans. Therefore, the expansion of maritime trade was not the primary cause of the oases' downfall; rather, localized environmental collapse dismantled the overland network.
In the argument given, the two bolded portions play which of the following roles?
- The first is a position that the argument seeks to refute; the second is an intermediate conclusion offered in support of the argument's main conclusion.Answer
- BThe first is a claim that the argument accepts as true; the second is the main conclusion of the argument.
- CThe first is a position that the argument opposes; the second is the main conclusion of the argument.
- DThe first is background information supporting the author's overall position; the second is evidence that undermines the author's main conclusion.
- EThe first is a hypothesis that the author supports; the second is a factual finding that challenges that hypothesis.