Final answer:
b. sensitized T-lymphocytes Sensitized T-lymphocytes are part of the adaptive immune response, which is specific and develops a memory of pathogens. This system includes helper T cells and cytotoxic T lymphocytes, and leads to the production of memory cells for a stronger, faster response upon re-exposure to pathogens.
Step-by-step explanation:
A specific defense for the body is represented by sensitized T-lymphocytes. These cells are part of the adaptive immune response, which is a highly specialized and effective system that targets specific pathogens. This response is slower to develop but provides a strong defense by remembering pathogens from previous encounters. Antigen-presenting cells (APCs) display antigens on Major Histocompatibility Complex (MHC) molecules to T cells. When a T cell with a receptor specific to that antigen binds to the APC it can differentiate and proliferate into helper T cells (TH cells) or cytotoxic T lymphocytes (CTLs).
These TH cells assist in stimulating B cells, which then differentiate into plasma cells that make antibodies, while CTLs can induce apoptosis in infected cells. The generation of memory cells ensures that on re-exposure to the same pathogen, the body can mount a faster and stronger immune response without the assistance of the innate immune system.The specific defense for the body is intact skin and mucous membranes. These physical barriers act instantaneously to prevent pathogenic invasion into the body tissues. They provide a first line of defense by preventing the entry of pathogens.