In which of the following organisms is the foot displaced to the neighborhood of the mouth and divided into arms?

Which invertebrate phylum exhibits unisexual or hermaphrodite conditions,external or internal fertilization,and direct or indirect development?

In which animal is the body divided into a head,muscular foot,and visceral hump?

Visceral mass undergoes torsion in which of the following classes of Mollusca?

The connecting link between $Annelida$ and $Mollusca$ is:

Open circulatory system is found in: