Proliferation of T-cells in response to antigen presentation is accompanied by enlargement of __ a. lymph nodes b. Thymus c. size of antibody d. size of B-cell

The correct answer is a. lymph nodes.<br /><br />When T-cells proliferate in response to antigen presentation, it is accompanied by the enlargement of lymph nodes. Lymph nodes are small, bean-shaped structures that are part of the lymphatic system. They play a crucial role in the immune response by filtering lymph fluid and housing immune cells, including T-cells.<br /><br />When an antigen (a foreign substance) enters the body, it is captured by dendritic cells and presented to T-cells in the lymph nodes. This triggers the activation and proliferation of T-cells, which helps to mount an immune response against the antigen. As a result, the lymph nodes enlarge to accommodate the increased number of T-cells and other immune cells that are involved in the immune response.<br /><br />Option b, the thymus, is not the correct answer. The thymus is an organ where T-cells mature, but it does not enlarge in response to antigen presentation.<br /><br />Option c, the size of antibody, is not the correct answer. The size of an antibody molecule does not change in response to antigen presentation.<br /><br />Option d, the size of B-cell, is not the correct answer. B-cells are a different type of immune cell that produce antibodies, but their size does not change in response to antigen presentation.