Which class includes squid and octopus?

Which class includes squid and octopus?

• A. Crustacea
• B. Cephalopoda
• C. Gastropoda
• D. Asteroidea

Answer: (B)

Cephalopods are the class that includes squid and octopus. They’re marine molluscs with a distinct head, a ring of arms or tentacles around the mouth, and often a reduced or internal shell. This arrangement, along with jet propulsion (water pushed through a siphon for rapid movement), a beak-like jaw, and a highly developed nervous system, marks them as active, predatory cephalopods. Their ability to change color and pattern with chromatophores also reflects their advanced control of body coloration. Crustaceans, like crabs and shrimp, have segmented bodies with jointed limbs and often multiple pairs of antennae and gills, not the characteristic head-and-arms layout of cephalopods. Gastropods, such as snails and slugs, typically have a muscular foot and a single shell (often spiraled) and lack the multi-armed configuration. Asteroidea are star-shaped echinoderms with radial symmetry and a water vascular system, not a head-and-appendages arrangement.

Cephalopods are the class that includes squid and octopus. They’re marine molluscs with a distinct head, a ring of arms or tentacles around the mouth, and often a reduced or internal shell. This arrangement, along with jet propulsion (water pushed through a siphon for rapid movement), a beak-like jaw, and a highly developed nervous system, marks them as active, predatory cephalopods. Their ability to change color and pattern with chromatophores also reflects their advanced control of body coloration.

Crustaceans, like crabs and shrimp, have segmented bodies with jointed limbs and often multiple pairs of antennae and gills, not the characteristic head-and-arms layout of cephalopods. Gastropods, such as snails and slugs, typically have a muscular foot and a single shell (often spiraled) and lack the multi-armed configuration. Asteroidea are star-shaped echinoderms with radial symmetry and a water vascular system, not a head-and-appendages arrangement.