Concept:Jointed legs are a defining feature of the phylum Arthropoda, which includes insects, spiders, and crustaceans.
Explanation:Arthropods have a segmented body, an exoskeleton, and jointed appendages (legs).
They are the largest phylum in the animal kingdom.
Examples: Insects (butterflies, ants), arachnids (spiders, scorpions), and crustaceans (crabs, shrimp).
Other phyla lack jointed legs.
Mollusca have a soft body and a muscular foot.
Nematoda are roundworms with a smooth, unsegmented body.
Echinodermata have a star-like body and tube feet, not jointed legs.
Answer:C. Arthropoda
