The word spotted(2^nd paragraph)can best be relaced by ______.

A．it is a space station
B．it is an ideal place for the investigation of glaciology
C．there is the mysterious dry valley
D．it can help people detect global environmental changes

A．There is a cluster of island west of the Transantartic Mountain.
B．Scientific research on Antarctica only centers on the ice and snow there.
C．Dry valleys may be a place to dispose of our pollutants.
D．All the countries on earth should be concerned about the health of the West Antarctic Ice Sheet.