Innate immunity is the body's first line of defense against pathogens, such as bacteria and viruses. It consists of physical barriers, like the skin and mucous membranes, as well as immune cells that respond quickly to infections. This type of immunity is non-specific, meaning it targets a wide range of invaders without recognizing specific pathogens. Unlike adaptive immunity, which develops over time and targets specific threats, innate immunity is present from birth. Key components include white blood cells, macrophages, and natural killer cells, which work together to identify and eliminate harmful microorganisms before they can cause disease.