The lymph vessel flows from the tissue to the lymph nodes, flow to the largest lymphatic vessel in the thorax called thoracic duct, then drain to the subclavian vein.
The lymphatic vessel is a thin tubular organ made of the endothelial cell. It has a valve like the vein to prevent backflow of lymph. Lymphatic vessel delivers the lymph through the body and has a role in the immune system.
I am not sure if this is what you mean but organ? or a system?
Answer:
The correct answer is- Leukopenia
Explanation:
White blood cells are present in our blood which protect our body from foreign antigens like bacteria, viruses, etc. When these white blood cells decrease abnormally in number then this condition is called leukopenia.
White blood cells contain different cell which protect our body from different type of infections. So there are different types of leukopenia according to the particular white blood cell whose number became low.
For example when neutrophils number in the body decrease it is called neutropenia. So the correct answer is leukopenia.