How does the body protect itself from invaders?

The body protects itself from invaders, such as pathogens, through a coordinated immune response. The first line of defense includes physical barriers like skin and mucous membranes, which prevent entry. If invaders breach these barriers, the innate immune system responds quickly with inflammatory responses and white blood cells that attack and engulf pathogens. Additionally, the adaptive immune system activates specific responses, producing antibodies and memory cells to provide long-term immunity against future infections.