Glaciers present today have taken centuries to form. They keep on melting, forming rivers and lakes, and are essential for human survival in many places across the world. This melted ice is replaced by fresh snow that is converted into ice over time. Problems start when the water that is melting is more than the snow that is replacing it.
According to the paragraph, which of the following would be a problem?
1. Coral reefs vanishing.
2. Re-contamination of the Earth, due to the melting of glaciers which contain deposits of pesticides.
3. Global warming, which is increasing temperatures.
4. None of the above.