The first question is, again, badly written.
The icing potential depends on both total water content AND temperature.
Further, this potential vary differently if one is speaking of engine icing or airframe icing.
I understand that the question ought to have been written:
"A parcel of air's total water content (vapour +liquid + ice) is important for airframe and engine icing potential. When it cools this total water content:"
When you take the actual exam, you have to quickly go through each question reading it at face value then, as time permits, go through a second sweep figuring which are the badly written questions and what might have the author's intentions been.