Questions: Unit Exam - Ëarth Systems What is the main reason that desalination (removing salt from saltwater) is not used to make clean, fresh water in all geographic areas? Desalination technology is not a reality. Desalination costs too much to use everywhere. Desalination causes too much air pollution.

The answer is the second one: Desalination costs too much to use everywhere.

Explanation for each option:

1. Desalination technology is not a reality.

   • This option is incorrect because desalination technology is indeed a reality and is currently in use in various parts of the world, such as the Middle East and parts of California.

2. Desalination costs too much to use everywhere.

   • This option is correct. The primary reason desalination is not used universally is due to its high cost. The process requires significant energy and infrastructure investment, making it economically unfeasible for many regions, especially those with limited financial resources.

3. Desalination causes too much air pollution.

   • This option is incorrect. While desalination does have environmental impacts, such as the disposal of brine and energy consumption, air pollution is not the main concern associated with the process. The primary issue is the cost and energy requirements.

Summary: Desalination is not used to make clean, fresh water in all geographic areas primarily because it is too expensive to implement everywhere.