Then one strand of dna serves as a template for?

If the DNA is in the process of replication, then a single DNA strand will serve as a template for a new complementary DNA strand to form one of two new double-stranded DNA molecules.  If DNA is in the process of transcription, then the single DNA strand will serve as a template for a complementary strand of  RNA. The new RNA strand will remain a single strand, it will leave the nucleus and go to a Ribosome where it will be translated into an amino acid sequence.

"a.) well–developed vascular system."

rising temperatures because when water vapor in the air is cooled, it condenses. it turns back into a liquid and attaches to dust particles in the air. these very small water droplets group together to form clouds