Which of the following correctly describes an immune response?

The immune response is a complex and highly coordinated biological process that targets specific pathogens, and option C accurately captures this idea. It highlights that the immune response involves a specific reaction to distinct pathogens, which is a cornerstone of adaptive immunity. This specificity is primarily achieved through the recognition of unique antigens present on pathogens, leading to the activation of B cells and T cells, resulting in the production of antibodies tailored to those antigens. This antibody production is crucial for neutralizing pathogens and helping in their elimination.

The detailed mechanism of this response allows the immune system to remember previously encountered pathogens, enabling a more rapid and effective response during subsequent exposures, which is a principle feature of immunological memory. This selective targeting distinguishes it from other less specific immune responses.

In contrast, the other options do not accurately reflect the characteristics of immune responses. Option A incorrectly suggests that the immune system focuses solely on toxins, which disregards its role in targeting various types of pathogens, including bacteria and viruses. Option B implies an indiscriminate attack on all foreign substances, which does not accurately encompass the specificity and memory features of the adaptive immune response. Option D describes a non-specific reaction, which pertains more to the innate immune responses, such as inflammation and phagocytosis