Why two major strategies does the immune system use to fight pathogens?

Innate immunity

The innate immune system is the first line of defense against pathogens. It is made up of physical barriers, such as the skin and mucous membranes, as well as chemical barriers, such as stomach acid. Innate immunity also includes cells that can recognize and attack pathogens, such as macrophages and natural killer cells.

Adaptive immunity

The adaptive immune system is the second line of defense against pathogens. It is made up of cells that can recognize and attack specific pathogens. Adaptive immunity is also responsible for immunological memory, which allows the body to mount a faster and more effective response to a pathogen that it has encountered before.

Why two major strategies?

The immune system uses two major strategies to fight pathogens because it needs to be able to respond to a wide variety of threats. Some pathogens are very easy to kill, while others are very difficult to kill. The innate immune system is able to quickly and effectively kill most pathogens, but it is not able to kill all pathogens. The adaptive immune system is able to kill pathogens that the innate immune system cannot, but it takes longer to mount a response. By using two major strategies, the immune system is able to provide a fast and effective response to a wide variety of pathogens.