Which of the following would happen if a brain injury damaged the cells that secrete cerebrospinal fluid?

Lack of conduction

reduction in brain blood flow

decrease in reflex speed

buildup of metabolic waste

The answer is build up of metabolic waste.

The cerebrospinal fluid (CSF) is a viscous liquid the surrounds and suspends the brain in it. The CSF serves the function of protecting the brain from physical damage by acting as a cushion. It also provides nourishment to the brain tissues, and removes metabolic waste generated by the cells in the brain. The choroid plexuses, ventricles, and ependymal cells produce the cerebrospinal fluid. A damage to these cells will lead to the loss of CSF production causing a build up of waste within the brain.