If all of the Earth's water were placed into a gallon jug, the freshwater would equal _____

• a single teaspoon
• a single tablespoon
• half a cup
• a single cup

Of the three blue dots in the image, the biggest one represents _____

• all of the water on our planet
• all of the salt water on our planet
• all of the liquid fresh water on our planet
• all of the surface freshwater that is accessible

Of the three blue dots in the image, the medium-sized dot represents _____

• all of the water on our planet
• all of the salt water on our planet
• all of the liquid fresh water on our planet
• all of the surface freshwater that is accessible

Of the three blue dots in the image, the teeny-tiny dot represents _____

• all of the water on our planet
• all of the salt water on our planet
• all of the liquid fresh water on our planet
• all of the surface freshwater that is accessible

Holding about one-fifth of the world's freshwater, what is the deepest lake in the world?

• North America's Lake Superior
• Africa's Lake Chad
• Russia's Lake Baikal
• Africa's Lake Tanganyika

Which species of freshwater seal is found in Lake Baikal?

• the Caspian seal
• the nerpa
• the Ladoga seal
• the Saimaa ringed seal 

How have the nerpa adapted to the thick ice that covers Lake Baikal in winter?

• their flippers are notably big and strong
• their skull is extra thick
• they have higher than average body fat
• their eyes are extra sensitive

The nerpa use their super strong flippers to _____

• battle other nerpa for territory
• crawl onto large rocks 
• swim great distances under the ice
• make breathing holes in the ice

Lake Chad is located on the edge of _____

• the Kalahari Desert in Africa
• the Gobi Desert in China
• the Sahara desert in Africa
• the Arabian Desert in Asia

To deal with a lack of water , the addax antelope _____

• have longer legs than usual
• change the color of their hair
• grow long horns
• have humps like camels