Read the given passage carefully and answer the questions that follow.
Mountains occupy about a quarter of the Earth’s land, harbour most of its biodiversity hotspots and supply fresh water to an estimated half of humanity. Present on every continent, mountains include a multitude of ecosystems holding many unique species such as snow leopards and mountain gorillas. They are also home to great cultural diversity among people adapted to the challenges of mountain life. Their special traditions and breath-taking scenery attract ever-growing numbers of tourists.
Mountain regions are particularly sensitive to degradation from both human pressures and climate change. Steep slopes mean the clearing of forest for farming, settlements or infrastructure can cause serious soil erosion as well as the loss of habitat. Erosion and pollution harm the quality of water flowing downstream. Climate change threatens the quantity and timing of water supplies to farms, cities, industry and power stations. Fast-rising temperatures are forcing mountain species, ecosystems and the people who depend on them to adapt or migrate.
Which of the following most accurately states the central idea of the passage?