Which of the following is true about polychaete worms?

• A. They are exclusively terrestrial organisms.
• B. They belong to the phylum Arthropoda.
• C. They possess parapodia used for locomotion and respiration.
• D. They lack segmentation in their body structure.

Answer: (C)

Verified step by step guidance

1. Understand the classification of polychaete worms: Polychaetes are a class of annelid worms, meaning they belong to the phylum Annelida, not Arthropoda. Annelids are characterized by their segmented body structure.
2. Clarify their habitat: Polychaete worms are primarily marine organisms, not terrestrial. They are commonly found in ocean environments, living in burrows, tubes, or free-swimming.
3. Examine their body structure: Polychaetes have a segmented body, which is a defining feature of annelids. Segmentation allows for greater flexibility and specialization of body parts.
4. Identify the function of parapodia: Polychaetes possess parapodia, which are paired, fleshy appendages on each segment. These structures are used for locomotion and respiration, aiding in movement and gas exchange.
5. Eliminate incorrect statements: Based on the above clarifications, the correct statement is that polychaete worms possess parapodia used for locomotion and respiration. The other options are incorrect because they are not terrestrial, do not belong to Arthropoda, and do not lack segmentation.