What is a D1 lymph nodes dissection?

It depends as to which organ drainage the lymph node has. If there is only one lymph node needed say for histological test or biopsy only one incision is fine. But i think, generally it takes only...

Lymph protect your body

A lymph node (pronounced /ˈlɪmf noʊd/) is a small circular ball shape organ of the immune system, distributed widely throughout the body and linked by lymphatic vessels. Lymph nodes are garrisons...

yup. But in such a way that at lymphatic nodes the bacteria and viruses are destroyed so in this way lymph is filltered.