The correct answer is B: Groundwater.
Explanation:
Groundwater is the most commonly used source of drinking water by humans. Here is a detailed explanation:
1. Groundwater: Groundwater refers to the water that is stored beneath the Earth's surface in porous rocks and soil. It accumulates in underground aquifers and can be accessed through wells or springs. Groundwater is considered a reliable and sustainable source of drinking water.
2. Advantages of Groundwater: There are several reasons why groundwater is preferred as a drinking water source:
- Purity: Groundwater is often naturally filtered as it seeps through layers of soil and rock, making it relatively free from pollutants and contaminants.
- Availability: Groundwater is abundant in most regions, providing a consistent supply of water throughout the year.
- Reliability: Unlike surface water sources like rivers and lakes, groundwater is less susceptible to variations in weather conditions or seasonal changes.
- Protection: Groundwater is less vulnerable to contamination from external sources, such as industrial pollution or surface runoff, as it is stored underground and protected by layers of soil and rock.
3. Other Options: While there are alternative sources of drinking water, they are not as commonly used as groundwater:
- Sea water: Sea water is abundant but requires extensive desalination processes to remove the high salt content, making it expensive and less accessible for drinking purposes.
- Glaciers: Glaciers are a significant source of freshwater, but they are typically found in remote and inaccessible locations, limiting their use as a drinking water source for most populations.
In conclusion, groundwater is the most widely used source of drinking water due to its purity, availability, reliability, and protection from contamination.