Final answer:
Memory cells are the key components of the adaptive immune system that recognize and respond to attacks by a pathogen that has attacked in the past (3). They ensure a rapid and robust immune response during subsequent exposures to the same pathogen.
Step-by-step explanation:
The components of the immune system that recognize and respond to attacks by a pathogen that has attacked in the past are memory cells.
Memory Cells and Immunological Memory
Memory cells are a critical component of the adaptive immune system. They are long-lived cells that remember past infections and enable the immune system to launch a swift and robust response upon re-exposure to the same pathogen. This rapid response is often so effective that it eliminates the pathogen before it can cause significant damage or symptoms, which is the basis of immunological memory.
Memory B cells remain in the body after the principal immune response to a pathogen and are responsible for the long-term immunity against that specific antigen. When these memory cells encounter the same antigen again, they quickly differentiate into plasma cells that produce specific antibodies to fight off the infection. As for T cells, there are memory T cells that similarly retain the template for the specific antigen and can quickly respond to subsequent exposures.