Dehydration synthesis is a process in which

Water (H2O) is drawn out of two small molecules to combine them into one large molecule

the correct answer, according to e2020, is the second choice there is an occluded front in region a and a cold front in region b.

enhanced global partnerships and exploration capabilities may advance international preparedness for protecting the earth from catastrophic events such as some asteroid strikes, advancing collaborative research on space weather and protecting spacecraft by developing new means for space debris removal.