Which of the following sets of animals belongs exclusively to the class Osteichthyes?

Step-by-step solution

The correct answer is option (2). Hippocampus (Sea horse), Exocoetus (Flying fish), and Pterophyllum (Angelfish) are all examples of bony fishes belonging to the class Osteichthyes. Option (1) is incorrect because Scoliodon (Dog fish) is a cartilaginous fish belonging to the class Chondrichthyes. Option (3) is incorrect because Trygon (Sting ray) is a cartilaginous fish. Option (4) is incorrect because Petromyzon (Lamprey) is a jawless vertebrate belonging to the class Cyclostomata. Answer: Hippocampus, Exocoetus,