Immune system defend against disease, while immune system leaves the body susceptible to a number of diseases.

Innate; Adaptive Explanation: The innate immune system is a nonspecific immune system which provides a general defense against pathogens and mostly fight against bacterial infections. The adaptive immune system are also called specific immune response where particular agents like the so-called antibodies target very specific pathogens that the body has already had contact with. But both the innate and adaptive immune systems complement each other in any reaction to a pathogen or harmful substance, and are closely connected with each other.

C) reflection (i also looked up the other choices just to make sure)