Given a scientific question, generate a correct answer to it.

[EX Q]: Most hydrozoa have both polyp and what forms in their life cycle?
[EX A]: medusa

[EX Q]: What tool do scientist's use to show the evolutionary pathways and connections among organisms?
[EX A]: phylogenetic tree

[EX Q]: Newly formed what aggregates into threads that form the framework of the clot?
[EX A]:
fibrin