A. They are very sensitive to surrounding stimuli. B. T……

Certainly no creature in the sea is odder than the common sea cucumber(海参). All living creatures, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about an odd animal that, among other eccentricities, eats mud, feeds almost continuously day and night but can live without eating for long periods, and can be poisonous hut is considered supremely edible by gourmets(美食家)
For some fifty million years, despite all its eccentricities, the sea cucumber has subsisted on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow water, or on the surface of mud fiats. Common in cool water on both Atlantic and Pacific shores, it has the ability to suck up .mud or sand and digest whatever nutrients are present.
Sea cucumbers come in a variety of colors, ranging from black to reddish-brown to sandcolor and nearly white. One form even had vivid purple tentacles. Usually the creatures are cucumbers-shaped——hence their name——and because they are typically rock inhabitants, this shape, combined with flexibility, enables them to squeeze into narrow cracks where they are safe from predators and ocean currents.

A. They are very sensitive to surrounding stimuli.
B. They are similar to those of most sea creatures.
C. They are completely defenseless when attacked.
D. They are intelligent sea creatures.