Which phylum includes arthropods?

Which phylum includes arthropods?

• A. Mollusca
• B. Chordata
• C. Echinodermata
• D. Arthropoda

Answer: (D)

Grouping animals by phyla is about shared, defining traits. Arthropods sit in the phylum Arthropoda because they all have a tough outer exoskeleton made of chitin, a segmented body, and jointed appendages that allow a wide range of movement. This combination distinguishes them from other phyla: mollusks are mostly soft-bodied and often have shells; chordates have a notochord at some life stage (including vertebrates); and echinoderms show radial symmetry and use a water vascular system. So, Arthropoda is the phylum that includes arthropods.

Grouping animals by phyla is about shared, defining traits. Arthropods sit in the phylum Arthropoda because they all have a tough outer exoskeleton made of chitin, a segmented body, and jointed appendages that allow a wide range of movement. This combination distinguishes them from other phyla: mollusks are mostly soft-bodied and often have shells; chordates have a notochord at some life stage (including vertebrates); and echinoderms show radial symmetry and use a water vascular system. So, Arthropoda is the phylum that includes arthropods.