<prompt> In which of the following sites do lymphocytes become immunocompetent?Germinal center of secondary lymphoid nodulesWhite pulp of the spleenThymic coexRed pulp of the spleen  <response>: T lymphocytes mature and become immunocompetent in the coex of the thymus, B lymphocytes mature and become immunocompetent in the bone marrow. After an antigenic challenge, lymphocytes proliferate and differentiate in various lymphoid tissues 