Which of the following is a role of lymph nodes?

They return lymph to circulation.

They produce lymph.

They filter lymph.

They produce red blood cells.

Answer: They filter lymph.

Explanation: Lymph nodes filter lymph, a fluid that comes from the blood plasma and passes through the lymph nodes; small structures that consist of immune cells. Their function is to engulf foreign parcticles. They prevent these foreign matters from circulating in the blood stream, playing a very important role in the immune system.