The remaining valid use of “medicinal leeches” is to

When earthworms copulate, each stores the other’s sperm in chambers called a/an

The body wall of an annelid consists of

The cephalopod nervous system is best described as

Select the list of characteristics typical of annelids.

The circulatory system in the earthworm

In contrast to roundworms, how do segmented worms elongate or stretch lengthwise?

The polychaetes

Cultured pearls are made by

Of all of the freshwater organisms, more freshwater clams are becoming endangered than other species. What is the likely reason?