The Mekong River is special. Each October it does something amazing: It shoots balls of fire into the sky. There have been many stories about the fireballs. Some people say there is a giant serpent, the naga, that spits the fireballs into the sky. But scientists say the naga is not real. They say that gas builds up beneath the river. When the gas floats to the top, it mixes with air. This turns the gas into fire. The fire then shoots up into the sky.

Scientists ________ the fireballs.
Anamed Bexplained
Cremoved Dprepared