In the eyes of the Republicans, the donkey is considered as______.

A．the ice can easily just slip into the ocean
B．volcanoes caused the ice to melt
C．melting just in the Northern hemisphere would have been impossible
D．researchers often use the computer models to help their research work

A．a computer model
B．studies which show ice melted equally in the North and the South during the ice age
C．most of the ice melted in the Northern hemisphere (半球) during the 30,000 year long ice age
D．a survey result