Final answer:
Microglia are the cells in the brain that help destroy pathogens and damaged tissue, performing a phagocytic role similar to macrophages.
Step-by-step explanation:
The cells that help destroy pathogens and damaged tissue in the brain are microglia. These cells act as the central nervous system's (CNS) first line of immune defense, functioning similarly to macrophages found in other parts of the body. Microglia actively scavenge the CNS for damaged neurons, plaques, and infectious pathogens. Their phagocytic activity is essential for maintaining brain tissue health by clearing out unwanted debris and fighting off potential threats. Therefore, the correct answer to which cells help destroy pathogens and damaged tissue in the brain is d. Microglia.