【简答题】Unique to poultry, it is located above the cloaca and connected with the cloaca. Its main function is to produce B lymphocytes. The organ involved in humoral immunity is( ).
【简答题】Unique to poultry, it is located above the cloaca and connected with the cloaca. Its main function is to produce B lymphocytes. The organ involved in humoral immunity is the( ).