What process allows the immune system to remember previous infections?

The process that allows the immune system to remember previous infections is known as clonal selection. When the body encounters a pathogen, specific immune cells, primarily B and T lymphocytes, are activated. Upon activation, these cells undergo clonal selection, where those that can recognize and bind to the specific antigens of the pathogen proliferate and differentiate into two main types of cells: effector cells and memory cells.

Effector cells are responsible for the immediate response to the infection, while memory cells remain in the body long after the infection has resolved. These memory cells ensure that if the same pathogen is encountered again in the future, the immune system can respond more rapidly and effectively. This concept of immunological memory is crucial for the effectiveness of vaccines and provides long-term protection against previously encountered pathogens.

In contrast, other processes like phagocytosis, antigen presentation, and immune tolerance serve different roles in the immune response. Phagocytosis involves the engulfing and destruction of pathogens by phagocytes. Antigen presentation is the process by which immune cells display antigens on their surface to help activate T cells. Immune tolerance refers to the mechanisms that prevent the immune system from attacking the body's own cells. While these processes are important for various aspects of