Lobed mouth structure "prostomium" is a characteristic ofAAnnelidsBCnidariansCPlatyhelminthesDChordates

Break Down the Problem

1. Identify the term "prostomium" and its association with various animal phyla.
2. Evaluate each option in the context of the term.

Relevant Concepts

• The prostomium is an anatomical term typically associated with certain invertebrates, specifically in the context of their mouth structure.

Analysis and Detail

1. Annelids: They are segmented worms like earthworms and leeches. Annelids do have a prostomium which helps in feeding.
2. Cnidarians: This group includes jellyfish and corals, which do not have a prostomium; they have a more simple body structure without a distinct segmented mouthpart.
3. Platyhelminthes: These are flatworms and do not have a prostomium; their body structure is more simplified and lacks segmentation.
4. Chordates: This is a diverse group that includes vertebrates. They do not have a prostomium; their mouth parts vary widely but are more advanced than the basic structure found in the mentioned invertebrates.

Verify and Summarize

Given the definitions and structures of the mentioned groups, it’s clear that only Annelids possess the lobed mouth structure known as a prostomium.

Final Answer

A. Annelids