What percentage of Earth's surface is covered by water?

• Over 70%

• 50%

• 30%

• 90%

Water pollution can harm any living organism on Earth and cause damage to land and other resources. Which of the following is NOT a source of water pollution?

• Farming in rural areas

• Waste from industry

• Natural rainfall

• Waste from dense populations

Water pollution can make water unusable as a resource. True or False?

• True

• False

The process of erosion involves the breaking down and carrying away of particles of ___.

New technologies in wastewater treatment facilities use filters, microorganisms, and chemical reactions to remove ___.