lungs, trachea spleen, thymus kidneys, bladder pancreas, pituitary gland
I gave my students this multiple choice question: Which organs belong to the lymphatic system?

Only one answer is correct among these 4 choices:
- lungs, trachea
- spleen, thymus
- kidneys, bladder
- pancreas, pituitary gland

Could you tell me which one is correct?

spleen, thymus