Which term refers to a mollusk whose body includes tentacles attached to its head?

Which term refers to a mollusk whose body includes tentacles attached to its head?

• A. Gastropod
• B. Tentacle
• C. Cephalopod
• D. Bivalve

Answer: (C)

The feature being tested is the body plan of mollusks, specifically how the head region relates to the tentacles. Cephalopods are the group where the foot has evolved into a head region that bears arms and, in many species, long feeding tentacles that originate near the mouth. This means the tentacles are effectively attached to the head, a hallmark of octopuses, squids, cuttlefish, and nautiluses. This contrasts with gastropods, which have a head with sensory tentacles but whose main structure is a muscular foot, not long tentacles arising from the head. Bivalves lack a distinct head and do not have such tentacles. So the term that best fits a mollusk with tentacles attached to its head is cephalopod.

The feature being tested is the body plan of mollusks, specifically how the head region relates to the tentacles. Cephalopods are the group where the foot has evolved into a head region that bears arms and, in many species, long feeding tentacles that originate near the mouth. This means the tentacles are effectively attached to the head, a hallmark of octopuses, squids, cuttlefish, and nautiluses. This contrasts with gastropods, which have a head with sensory tentacles but whose main structure is a muscular foot, not long tentacles arising from the head. Bivalves lack a distinct head and do not have such tentacles. So the term that best fits a mollusk with tentacles attached to its head is cephalopod.