Which group includes soft-bodied animals typically protected by a hard covering?

The group that includes soft-bodied animals typically protected by a hard covering is the Phylum Mollusca. This phylum encompasses a diverse range of organisms, including snails, clams, and octopuses. Mollusks are characterized by their soft bodies, which are often supported by a hard external shell made of calcium carbonate. This shell provides protection against predators and environmental stresses.

Mollusks also exhibit various adaptations, such as a muscular foot for movement and a mantle that secretes the shell. The presence of a hard shell is a defining feature of many mollusks, distinguishing them from other phyla. This protective covering allows mollusks to thrive in a variety of habitats, from marine and freshwater environments to terrestrial ecosystems.

In contrast, the other phyla listed do not share this characteristic. Phylum Porifera, for example, includes sponges that lack true tissues and organs and have a porous body structure. Phylum Nematoda encompasses roundworms, which have a tough outer cuticle but lack a hard shell. Phylum Annelida contains segmented worms, such as earthworms and leeches, that also do not possess a hard protective covering.