Which Correctly Describes the Evolutionary Origin and Adaptive Radiation of Molluscs

Question

Which correctly describes the evolutionary origin and adaptive radiation of molluscs?
A)Molluscs originated in freshwater and invaded both terrestrial and marine environments
B)Molluscs originated on land,all classes then invaded both freshwater and marine environments
C)Molluscs originated on land,all classes then invaded freshwater and the bivalves and gastropods invaded marine environments
D)Molluscs originated in the sea,both bivalves and gastropods invaded marine environments and the land
E)Molluscs originated in the sea,bivalves and gastropods invaded brackish and freshwater environments,and just gastropods invaded the land

Accepted Answer

Molluscs are believed to have originated in the sea, with certain groups like bivalves and gastropods adapting to brackish and freshwater environments. Gastropods are the only molluscs that have extensively colonized terrestrial environments.