The right answer is: phagocytosis of foreign materials
The cell 1 is a microglial cell
Microglia are a set of microglial cells, which make up a quarter of the cells of the central nervous system.They have a star shape, are small and can move. Related to macrophages (it has the same morphology and does the same function as phagocytosis of antigens), their role is to ensure the immunity of the nervous system.