Read the following statements regarding the members of class Cyclostomata: (a) All living members are ectoparasites on some fishes. (b) Their cranium and vertebral column are bony. (c) The circulatory system is of the open type. (d) After spawning in fresh water, they die within a few days. Choose the correct statements from the options given below:

Step-by-step solution

According to the characteristics of class Cyclostomata: Statement (a) is correct because all living members of the class Cyclostomata are ectoparasites on some fishes. Statement (b) is incorrect because their cranium and vertebral column are cartilaginous, not bony. Statement (c) is incorrect because the circulatory system in cyclostomes is of the closed type, not open. Statement (d) is correct because cyclostomes are marine but migrate to fresh water for spawning. After spawning, they die within a few days, and th