问题: AtthetopofJungfrau,whichtowers12,000feetabovethetownofInterlakeninSwitzerland,thetemperatureisusually_______.
A: containsalayerofozonegases.
B:about42degreescolderthanontheground.
C:21%oxygenbyweight.
D:lessthan1%ofxenonbyvolume
E:about75degreescolderthaninInterlaken
F:iswarmedbytheearth’sheat.
