How many chambers does the heart of these animals have?

Step-by-step solution

All living members of the class Cyclostomata are ectoparasites on some fishes.Cyclostomes have a sucking and circular mouth without jaws. Cyclostomes have an elongated body bearing 6-15 pairs of gill slits for respiration. Cyclostomes are marine but migrate for spawning to fresh water. After spawning, within a few days, they die. Their larvae, after metamorphosis, return to the ocean. After spawning, within a few days, Cyclostomes die.The mouth is located ventrally on these animals.The skin is tough, containing min