Which list correctly names the four major classes of arthropods?

Which list correctly names the four major classes of arthropods?

• A. Arachnids, Centipedes and Millipedes, Crustaceans, Insects
• B. Mollusks, Echinoderms, Annelids, Nematodes
• C. Sponges, Cnidarians, Mollusks, Echinoderms
• D. Plants, Fungi, Algae, Bacteria

Answer: (A)

Grouping arthropods into four main classes includes insects, arachnids, crustaceans, and myriapods. Arthropods share an exoskeleton, segmented bodies, and jointed appendages, and each class represents a major way these features are organized in different groups. Insects have three body segments and six legs; arachnids have two body segments and eight legs; crustaceans typically have two pairs of antennae and a variety of body forms; myriapods include centipedes and millipedes, with many body segments and many legs. The option that lists Arachnids, Centipedes and Millipedes, Crustaceans, and Insects matches these four groups, making it the correct choice. The other options describe non-arthropod phyla or other kingdoms altogether, so they don’t fit the category.

Grouping arthropods into four main classes includes insects, arachnids, crustaceans, and myriapods. Arthropods share an exoskeleton, segmented bodies, and jointed appendages, and each class represents a major way these features are organized in different groups. Insects have three body segments and six legs; arachnids have two body segments and eight legs; crustaceans typically have two pairs of antennae and a variety of body forms; myriapods include centipedes and millipedes, with many body segments and many legs. The option that lists Arachnids, Centipedes and Millipedes, Crustaceans, and Insects matches these four groups, making it the correct choice. The other options describe non-arthropod phyla or other kingdoms altogether, so they don’t fit the category.