Philippe Bouchet and colleagues conducted a massive survey of marine molluscs on the west coast of New Caledonia. Twenty percent of the species found were represented by a single specimen. What does that suggest about the diversity of molluscs in this area?
A) They did not look very hard for those 20 percent. B) Many of the species from this 20 percent are probably rare. C) There are only a few species of molluscs in the area. D) Most of the species from this 20 percent are quite common.