The ____ is an Extension of the Upper Body Wall

Question

The ____ is an extension of the upper body wall in mollusks.  
A) radula
B) mantle
C) gill
D) lung
E) siphon

Accepted Answer

The mantle is an extension of the upper body wall in mollusks. It surrounds the internal organs and produces the shell in species that have one. The radula is a feeding structure, gills and lungs are respiratory organs, and a siphon is a structure used for water movement in some species.