Platyhelminthes were the first organisms to have ____.
a. a fully developed brain
b. a notochord
c. a central nervous system
d. metamerism
e. an excretory system
Question 2Which worm has a segmented body plan?
a. Platyhelminthes
b. Nematoda
c. Roundworm
d. Polychaeta
e. Flatworm