Question

question 4 of 20 : select the best answer for the question. 4. nervous systems are required by animals to respond to stimuli and have complex senses such as taste, touch, sight, smell, or sound. these are carried by nerves to and from the brain and spinal cord. of all major animal phyla, which does not have nerves? a. cnidarians b. chordata c. annelids d. porifera mark for review (will be highlighted on the review page)

Explanation:

To solve this, we analyze each phylum:

• Option A (Cnidarians): They have a simple nervous system (nerve net), so they do have nerves.
• Option B (Chordata): Includes animals with well - developed nervous systems (brain, spinal cord), so they have nerves.
• Option C (Annelids): Have a nervous system with a ventral nerve cord and ganglia, so they have nerves.
• Option D (Porifera): Sponges (Porifera) lack true nerves or a nervous system. They are simple animals that rely on cell - to - cell communication and do not have the specialized nerve cells or structures seen in other phyla.

Answer:

D. Porifera