Final answer:
Bryozoans have a rudimentary nervous system and lack complex sensory organs, instead having simple sensory cells for environmental response.
Step-by-step explanation:
Bryozoans, which are aquatic invertebrate animals, have a rudimentary nervous system and lack complex sensory organs. As filter feeders, bryozoans use their tentacles to extract food particles from the water. These organisms are characterized by their small size, bilateral symmetry, and colonial living, forming structures like gelatinous blobs or encrustations. Unlike some other marine invertebrates, bryozoans do not possess distinct sensory organs like eyes or ears, but they do have sensory cells for basic environmental responses. Bryozoans also have an external skeleton to protect their colony of zooids, which are the individual units of bryozoan colonies.