Final answer:
The difference between denticulate ligaments and arachnoid involves the meninges of the CNS, with denticulate ligaments being extensions of the pia mater and the arachnoid being the middle protective layer.
Step-by-step explanation:
The difference between denticulate ligaments and arachnoid involves the meninges, which are the protective coverings of the brain and spinal cord. The correct answer to your question is D) Pia mater. Denticulate ligaments are extensions of the pia mater that anchor the spinal cord to the dura mater, preventing side-to-side movement. On the other hand, the arachnoid is the middle layer of the meninges named for the spider-web-like trabeculae that extend between it and the pia mater. The arachnoid defines a sac-like enclosure around the central nervous system (CNS) and is involved in the circulation and drainage of cerebrospinal fluid (CSF).