What punctuation and/or conjunction can be used to combine them

the coastal area of the antarctic are milder. precipitation in those regions averages up to eight inches per year.

milder; and precipitation
milder, precipitation
milder, and precipitation
milder and precipitation

What do the excerpts have in common? both point out the tragic nature of situations in which children make journeys without their parents. both describe what immigrant children must do to survive when traveling to the united states. both explain why most children want to leave central america without their parents. both indicate the tragic problems and their consequences that children in central america must face.