Which of the following is NOT a feature annelids are classified on: Metameres, Parapodia, Setae, Tentacles?

The annelids are classified based on several key features.

• Metameres (body segmentation) are a defining characteristic of annelids.
• Parapodia are paired, fleshy appendages found in many annelids (especially polychaetes) and are important for locomotion and classification.
• Setae (bristles) are chitinous structures present in most annelids, and their presence and arrangement are used in classification.
• Tentacles are not a universal feature used for classifying annelids. While some annelids may possess tentacles, they are not a primary distinguishing characteristic for the entire phylum in the same way as segmentation, parapodia, or setae.

The feature that annelids are classified based on EXCEPT is tentacles.

The final answer is $\text{A}$