Answer:
true coelom.
Step-by-step explanation:
The Annelida Phylum gathers the animals with cylindrical and segmented body structure, with evident outer rings, also internally subdivided (true metamerization).
These bilateral symmetry invertebrates have three embryonic (triblastic) leaflets, and a general organism cavity called a coelom. In the outer surface of some species, in the epidermal cuticle, there are small hairs (bristles) that support during locomotion, and the amount of these filaments is a criterion used in the differentiation of organisms.