1. Fluid Balance
2. Fat absorption
An immune system is a system of biological structures and processes within an organism that protects against disease. In order to function properly, an immune system must detect a wide variety of agents, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue.
Here is a link that will help you to understand more about the lymphatic system:
Here is a video on how the body works according to our immunity:
End of Chapter 19