Passage: "Coral reefs, often called the 'rainforests of the sea,' are among the most biodiverse ecosystems on Earth. Their calcified structures, built by tiny polyps over millennia, provide habitat and sustenance for an astonishing array of marine life. However, these vital ecosystems are increasingly threatened by climate change, ocean acidification, and pollution. While efforts like establishing marine protected areas and promoting sustainable fishing practices offer some hope, the sheer scale of the anthropogenic impacts necessitates a global, coordinated response far beyond current initiatives to prevent irreversible degradation." The phrase "rainforests of the sea" serves primarily to:
✓ Correct Answer: Option B
The phrase directly follows the statement that coral reefs are 'among the most biodiverse ecosystems on Earth.' The analogy to rainforests, known for their biodiversity, serves to underscore this point about coral reefs.