Brutal 66

Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation, acting as global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate the destruction of the ozone layer by reacting with chloroflurocarbons (CFC's).

A) acting as global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate
B)acting as a global thermostat and thus keeping Earth either from burning up or freezing over, while also accelerating
C)act as a global thermostat and thus keep Earth from either burning up or freezing over, while also accelerating
D)they act as a global thermostat that thus keeps the Earth either from burning up or freezing over, even though it also accelerates
E)they act as a global thermostat to thus keep Earth from either burning up or freezing over, but they also accelerate

Explanation:
Although ice particles in the upper atmosphere benefit Earth in that they reflect and absorb solar radiation, acting as global thermostat and thus keeping Earth from either burning up or freezing over, they also accelerate the destruction of the ozone layer by reacting with chloroflurocarbons (CFC's)

Although...they also....

C is flawed after "while also accelerating" isnt correct

Should be A