What system filters fluid in the body mounts the attack against foreign substances in the body?

The lymphatic system filters fluid in the body and plays a crucial role in the immune response against foreign substances. It transports lymph, a fluid containing infection-fighting white blood cells, throughout the body and facilitates the removal of waste products. Lymph nodes, part of this system, act as filters where immune cells can detect and attack pathogens. Overall, the lymphatic system is essential for maintaining fluid balance and supporting the body's defense mechanisms.