True or False: The innate immune response relies solely on natural killer cells to effectively combat all types of infections and tumors.

False. The innate immune system uses many cells and mechanisms, not just natural killer cells, to fight infections and tumors. Macrophages, neutrophils, dendritic cells, and the complement system all act quickly to engulf pathogens, signal other cells, and create an inflammatory environment. NK cells are important for killing infected or cancerous cells, but they work alongside these other components. For example, a bacterial infection is first tackled by neutrophils that rush to the site and ingest bacteria before NK cells even arrive.