Which category does not consist of arthropods?

Worms are classified as annelids or nematodes, depending on the type, and do not belong to the arthropod phylum. Arthropods are characterized by their jointed legs, exoskeletons made of chitin, and segmented bodies, which are features that distinguish them from other types of invertebrates.

In contrast, insects, spiders, and ticks are all part of the arthropod family. Insects are the largest group of arthropods, with a diverse range of forms and habitats. Spiders belong to a group known as arachnids, which are characterized by having eight legs and no antennae. Ticks are also arachnids and share similar features with spiders, further solidifying their classification within the arthropod phylum.

Therefore, the presence of worms, which possess fundamentally different anatomical and biological structures, makes them the correct choice for a category that does not consist of arthropods.