Conversation so far:
lymph node clusters are found in which region
These areas are the inguinal nodes in the groin, the axillary nodes in the armpit, and the cervical nodes in the neck.
how big are lymph nodes
Lymph nodes are small bean-shaped structures that are usually less than 2.5 cm in length.

Question: what's the function
Self-contained rewrite: what's the function of lymph nodes