Which statement correctly lists the three major mollusk classes?

Which statement correctly lists the three major mollusk classes?

• A. Gastropods, Bivalves, and Cephalopods
• B. Gastropods, Cephalopods, and Annelids
• C. Bivalves, Echinoderms, Cephalopods
• D. Gastropods, Bivalves, and Mollusks

Answer: (A)

Identifying the major classes within the mollusk group. Mollusks are traditionally organized into three widely recognized classes: gastropods (snails and slugs), bivalves (clams, oysters, mussels), and cephalopods (octopus, squid, cuttlefish, nautilus). This combination correctly names the primary mollusk lineages studied in basic biology, reflecting the main anatomical and lifestyle differences among these animals. Other choices mix in organisms from completely different groups, like annelids (segmented worms) or echinoderms (starfish and relatives), which are not mollusks. One option even treats mollusks as a class, which isn’t accurate because Mollusca is the phylum, not a single class. Hence, the statement that lists gastropods, bivalves, and cephalopods is the correct one.

Identifying the major classes within the mollusk group. Mollusks are traditionally organized into three widely recognized classes: gastropods (snails and slugs), bivalves (clams, oysters, mussels), and cephalopods (octopus, squid, cuttlefish, nautilus). This combination correctly names the primary mollusk lineages studied in basic biology, reflecting the main anatomical and lifestyle differences among these animals.

Other choices mix in organisms from completely different groups, like annelids (segmented worms) or echinoderms (starfish and relatives), which are not mollusks. One option even treats mollusks as a class, which isn’t accurate because Mollusca is the phylum, not a single class. Hence, the statement that lists gastropods, bivalves, and cephalopods is the correct one.