A marine fish has a streamlined body, a ventral mouth, gill slits without an operculum, a tough skin with placoid scales and no air bladder. Males have claspers on the pelvic fins. Which class does it belong to?

© 2026 Lumi (Aikolumi Software Pvt Ltd). Original questions written by Lumi. Free to view and practise on this site. Copying, republishing or reproducing these questions, options or solutions, in print or online, is not permitted.