A、The reproductive cycle of barnacles. B、A new source of protein. C、Types of sea animals. D、The adhesive quality of barnacles. D

M: Did you watch undersea Discover), last night?
W: No, I missed it. Did you?
M: Yeah, it was pretty good...It was about barnacles.
W: Hmm.
M: You know how they stick themselves to stuff in the ocean ... like rocks or boats?
W: Uh—huh.
M: Well, they do that when they’re young, and then they stay in the same place forever.
W: It figures. Have you ever tried removing one of those things. Last summer I tried to scrape some off a pier...I had to give up after a while. You’d think they wouldn’t be able to stick like that undcrwater.
M: That’s one. reason scientists are-trying to figure out what their glue’s made of. It’s one of the strongest adhesive in nature, and it’s a natural protein, so it probably wouldn’t be harmful like some synthetic glues.
W: Really?
M: Yes. these biomedical researchers were talking about its possible uses. Orthopedists could use it for mending broken bones; or it could be used in dentistry.
W: I wish I’d seen that.