Final answer:
The Canadian Great Lakes contain 21% of the world's surface fresh water, which is the answer choice D. The world's freshwater is largely found in icecaps, glaciers, and underground, with less than 1% being easily accessible to humans. This distribution underlines the importance of the Great Lakes as a significant freshwater resource.
Step-by-step explanation:
The Canadian Great Lakes contain a significant portion of the world's surface fresh water. Specifically, they hold 21% of the world's surface fresh water. Therefore, the correct answer to the question is D. 21%. The Great Lakes are an essential surface water resource that plays a vital role in the global water distribution.
Looking at the broader picture of Earth's fresh water, 68.7% is contained in icecaps and glaciers, 30.1% in groundwater, and the remaining 0.9% in other forms such as soil moisture, vapor, etc. Surface water, which includes lakes, swamps, and rivers, accounts for only 0.3% of Earth's total freshwater, and of that, 87% is in lakes, 11% is in swamps, and 2% in rivers.
It's also important to note that Earth's oceans contain 97% of the planet's water, which is saline. The majority of Earth's freshwater is trapped as ice or underground, making it less accessible for human use. In fact, only about 1% of the world's fresh water is easily accessible to us. This scarcity is a key reason why access to drinking water is a critical global issue.