Multiple Choice, Single Answer
1 questions. Answer them all, then submit once for your section score.
Read the passage and answer the question.
Modern glacier monitoring relies less on infrequent field expeditions and more on continuous, automated observation. Networks of stakes drilled into the ice transmit data on surface melt via satellite links, while ground-penetrating radar reveals internal structure without disturbing the surface. Satellite altimetry, meanwhile, tracks subtle changes in elevation across entire ice sheets, allowing scientists to estimate volume loss over vast areas that would be impossible to survey on foot. Time-lapse cameras positioned on adjacent slopes capture calving events at glacier termini, providing visual confirmation of the numerical data. Because glaciers respond to climate signals with a lag of years, researchers stress that only sustained, multi-decade datasets—not isolated seasonal readings—can reliably distinguish genuine long-term retreat from short-term fluctuation.