Question

For much of the early nineteenth century, geologists attributed the distribution of erratic boulders across Northern Europe to diluvial currents or icebergs drifting across submerged continents. In 1837, Louis Agassiz proposed a radical alternative: a vast, continental ice sheet had once covered the region, transporting debris as it expanded and retreated. Initial reception among established geologists was largely hostile, as Agassiz’s hypothesis challenged the uniformitarian framework popularized by Charles Lyell, which favored gradual, ongoing marine processes over sudden, catastrophic terrestrial glaciation. To substantiate his model, Agassiz cited distinctive striations carved into bedrock—features that drifting icebergs could not systematically produce over elevated terrain. Subsequent field investigations by William Buckland in Scotland revealed identical striations, compelling key skeptics to reconsider. Consequently, what began as a highly contentious challenge to geological orthodoxy ultimately shifted the paradigm of Quaternary geology, demonstrating that terrestrial ice sheets could account for topography previously thought to require oceanic submergence.

Which of the following statements correctly describes the rhetorical function of a specific element within the passage? Consider each of the choices separately and select all that apply.