what is the role of the cerebrospinal fluid provides cushioning for the brain maintain a stable ionic concentration in the cns provides a pathway to the blood for waste

The correct answer is - provides cushioning for the brain.

Explanation:

The cerebrospinal fluid or CSF is a clear colorless fluid that is present within the tissue that surrounds the spinal cord and the brain of all vertebrates. The major and main role or function of CSF is to provide a cushion to the brain within the skull and acts as a shock absorber from the outer world impact for the central nervous system.

Other than providing a cushion for the most sensitive body part brain, CSF also transports nutrients and chemicals filtered from the blood and removes waste products from the brain.