Instructions: Given a scientific passage and an answer, generate a question for the given answer.
Input: Passage: Ray-finned fish include the majority of living fish species, including goldfish, tuna, salmon, perch, and cod. They have a bony endoskeleton and a swim bladder. Their thin fins consist of webs of skin over flexible bony rays, or spines. The fins lack muscle, so their movements are controlled by muscles in the body wall. You can compare their ray fins with the fleshy fins of lobe-finned fish in Figure below . Answer: ray-finned fish
Output:
What type of fish are the majority of living species?