Soru

For decades, oceanographers assumed the deep seabed was a vast, featureless plain, a silent desert of silt. In the early 1950s, geologist Marie Tharp began drafting detailed physiographic maps of the Atlantic floor using raw sonar data. Her maps revealed a massive, continuous mountain range bisecting the ocean. When Tharp pointed out a prominent V-shaped rift valley running down the center of this ridge, her colleague Bruce Heezen dismissed it as 'girl talk.' Heezen, like most scientists of the era, was highly skeptical of continental drift, and a central rift valley would provide undeniable evidence of tectonic plates pulling apart. Undeterred, Tharp persisted, eventually forcing Heezen—and the broader scientific community—to re-evaluate their entire understanding of Earth's dynamics.

Based on the passage, what is the primary rhetorical function of the statement that a central rift valley 'would provide undeniable evidence of tectonic plates pulling apart'?