One type of worm is the flatworm. Worms in the phylum Platyhelminthes are called flatworms because they have flattened bodies. There are more than 18,500 known species of flatworms.
CK-12 (Middle School)
How are flatworms similar to, but different from other invertebrates?
RST.1 - Analysis & Evidence, RST.4 - Key Terms
DEPTH OF KNOWLEDGE (DOK) LEVELS:
2,3Read this assignment in Actively Learn