Final answer:
Innate immunity is the natural defense we are born with, providing a first line of defense against pathogens, while adaptive immunity develops after exposure or vaccination.
Step-by-step explanation:
The immunity that we are born with, which provides protection against many harmful substances, is called innate immunity. This form of immunity is not induced by infection or vaccination; rather, it is a natural defense mechanism that comes from our genetic code and physiological makeup.
Innate immunity is always active and provides a first line of defense against pathogens. It includes barrier defenses like skin and mucosal surfaces, as well as internal defenses such as fever, inflammation, and natural killer cells. On the other hand, adaptive immunity develops after exposure to specific pathogens or through vaccination, which leads to artificially acquired active immunity.