Question

with advancing age, __________ become less responsive to antigens. additionally, __________ are less responsive, and antibody levels do not rise as quickly after antigen exposure.

Explanation:

As people age, the immune system undergoes changes. T - cells play a crucial role in cell - mediated immunity. With aging, T - cells become less responsive to antigens. B - cells are responsible for antibody production. In the elderly, B - cells are also less responsive, and as a result, antibody levels do not rise as quickly after antigen exposure compared to younger individuals. Macrophages are phagocytic cells and their main function is not directly related to the antibody - level - related response described here. Lymphocytes is a broad category that includes T and B cells, so the more specific and accurate pair is T cells and B cells.

Answer:

T cells; B cells