单项选择题
When an organism is completely encapsulated and preserved, it becomes a fossil, therefore turning into evidence of things that once lived.（）
A．thereby B．as a result of C．so D．in the end
A．does much harm ... smoking B．will do as much harm ... cigarettes C．will be doing as much harm ... smoking D．does as much harm ... cigarettes
A．but it is not B．but it is C．but they are not D．but they are