Cyclostomata, like lamprey eels and hagfish,
a. feed on other fish or invertebrates
b. have cartilage skeletons
c. reproduce by internal fertilization

It may be A but im am not so sure but anyways.
 
Good Luck

Pro insulin undergoes extensive posttranslational modification along the production pathway .

I’m not exactly sure what your trying to ask, but if it’s how an organelle is similar to a body system or a part a nucleus is like a in function. but i don’t fully understand what you’re trying to ask