2
Select the correct text in the passage.
Which sentence introduces the central idea of the passage?
(2) Snow and glaciers in these mountains contain the largest volume of freshwater outside of Earth's polar ice sheets, leading hydrologists to nickname this
region the Third Pole. One-seventh of the world's population depends on rivers flowing from these mountains for water to drink and to irrigate crops.
(3) Rapid changes in the region's climate, however, are affecting glacier melt and snowmelt. People in the region are already modifying their land-use
practices in response to the changing water supply, and the region's ecology is transforming Future changes are likely to influence food and water security
in India, Pakistan, China and other nations