Question

which of the following is the largest mass of lymphoid tissue and serves to filter the blood?
lymph nodes
spleen
peyers patches
tonsils

Explanation:

The spleen is the largest mass of lymphoid tissue in the body and filters the blood. Lymph nodes filter lymph, Peyer's patches are in the small - intestine mucosa for immune surveillance of gut contents, and tonsils are in the pharynx for immune defense of the upper respiratory and digestive tracts.

Answer:

Spleen