Which of the following is a specific element of the immune system?

Lymphocytes are a specific element of the immune system because they are primarily responsible for the adaptive immune response, which is tailored to recognize and remember specific pathogens. This group of white blood cells includes T cells and B cells, both of which play critical roles in identifying and responding to foreign invaders. T cells can directly kill infected host cells or help activate other immune cells, while B cells produce antibodies that specifically target antigens present on pathogens.

In contrast, other options such as neutrophils are part of the innate immune system and respond broadly to infections, lacking the specificity that characterizes lymphocytes. Erythrocytes, or red blood cells, are responsible for oxygen transport and do not play a direct role in the immune response, while platelets are involved in blood clotting and wound healing but are not components of the immune system. Thus, the defining characteristic of lymphocytes is their ability to specifically recognize and remember pathogens, making them a cornerstone of the adaptive immune response.