Of all the freshwater on Earth, what percent of it is actually accessible to us on the surface?

• less than one percent
• about three percent
• about thirty percent
• about fifty percent

A group of parts that work together as a whole is called _____

• conservation
• a zone
• a niche
• a system

Probably the biggest thing that humans do that negatively affects the hydrosphere is _____

• overharvesting
• polluting
• building dams
• removing dams

When people use more freshwater than can be replaced it's called _____

• overharvesting
• farming
• distributing
• fertilizing

When people put sewage or other waste in the water it's called _____

• overharvesting
• farming
• polluting
• dam building

A barrier built to  collect or redirect water is called a _____

• dam
• bridge
• tunnel
• waterway

Protecting things found in nature is called _____

• pollution
• conservation
• overharvesting
• squandering

The Elwha River is located in _____

• Olympic National Park in Washington State
• Yellowstone National Park in Wyoming
• Grand Canyon National Park in Arizona
• Yosemite National Park in California

What was built, nearly 100 years ago, that brought a lot of problems to the Elwha River?

• a massive factory
• a long bridge
• a large highway
• a giant dam

The Elwha River is home to all 5 species of native _____

• Atlantic tuna
• Pacific tuna
• Pacific salmon
• Atlantic salmon