The correct answer is: "It is the fluid that re-enters blood vessels."
The lymphatic system is a network of vessels, tissues, and organs that help maintain fluid balance in the body and defend against infections. Lymph is a clear fluid that circulates through the lymphatic system, and it plays an important role in returning excess interstitial fluid (the fluid that surrounds cells in tissues) back into the bloodstream. This helps maintain the proper balance of fluids in the body and prevents the buildup of excess fluid (edema) in tissues.
Lymph also carries immune cells and other components of the immune system that help defend against infections and diseases. However, lymph does not carry red blood cells, hormones, or protein products, which are transported by the blood vessels in the circulatory system.