Lee North, age 11, of Coventry,R.I., for her question:

.HOW DOES A WHELK GROW HIS SHELL?

The creatures that live in shell houses have special layers of skin called the mantle. These fleshy layers enfold their soft bodies like loose capes. The cells in the mantle extract calcium type chemicals from the water and process them to form a gummy secretion. This shell building material dries in the air. The mantle deposits it in layers around the edge of the shell—and the shell grows bigger and the whelk