Which statement best describes the main function of cerebrospinal fluid (CSF)?

• A. Buoyancy, nutrient delivery, and waste clearance
• B. Buoyancy only
• C. Nutrient delivery only
• D. Waste clearance only

Answer: (A)

Cerebrospinal fluid serves several integrated roles that keep the brain functioning properly. It provides buoyant support, which dramatically reduces the brain’s effective weight and helps cushion it within the skull. It also acts as a circulating medium that delivers nutrients and ions to neural tissue and helps remove metabolic wastes by exchanging substances between the CSF and brain interstitial fluid. In addition, CSF helps stabilize the chemical environment of the brain, contributing to homeostasis.

Because the best description combines all these functions—buoyancy, nutrient delivery, and waste clearance—the statement that lists all three is the most accurate. Focusing on only one aspect (just buoyancy, or just nutrients, or just waste removal) misses how CSF operates as a support system and a maintenance medium for brain tissue.