The author mentions catastrophic proglacial lake drainage events in order to:

During the Pleistocene epoch, cyclical expansions and retreats of continental ice sheets exerted profound controls on global hydrology and geomorphology. As continental glaciers locked up enormous volumes of precipitation as perennial ice, eustatic sea levels plummeted by as much as 120 to 130 meters during the Last Glacial Maximum (LGM) approximately 20,000 years ago. This volumetric drop exposed vast swaths of continental shelf, desiccating shallow epicontinental seas and creating temporary subaerial land bridges such as Beringia between Eurasia and North America. Conversely, interglacial warming stages triggered widespread melting, generating meltwater pulses that rapidly inundated coastal plains and carved immense scablands through catastrophic proglacial lake drainage events.

Answer and explanation

Correct answer: D. Illustrate how rapid glacial meltwater release dynamically transformed terrestrial landscapes.

  1. Step 1: Analyze the rhetorical purpose of the author's reference to "catastrophic proglacial lake drainage events" in the final sentence.
  2. Step 2: The author mentions that warming generated meltwater pulses that "rapidly inundated coastal plains and carved immense scablands through catastrophic proglacial lake drainage events." This example concretely demonstrates how intense hydrological releases shaped landforms.
Answer
Illustrate how rapid glacial meltwater release dynamically transformed terrestrial landscapes.

Practise more Academic Reading: Natural Sciences.

Free questions with an explanation for every one, and full timed TOEFL mock tests.

All Academic Reading: Natural Sciences questionsTake a mock test

More Academic Reading: Natural Sciences questions