What is the primary function of lymph?

The primary function of lymph is to maintain the body's fluid balance. Lymph is a clear fluid that circulates in the lymphatic system, serving crucial roles in the body. One of its main functions is to collect excess fluids and proteins from tissues, which helps to prevent swelling and ensures that the interstitial fluid remains at a stable level. When tissues are damaged or inflamed, lymph helps to drain the excess fluid away, thus supporting homeostasis in the body.

While lymph does have roles in transporting certain substances and contributing to immune function, its most fundamental role is in fluid balance. The other functions, such as transporting nutrients or acting solely as a defense mechanism, are secondary to its primary role in maintaining proper fluid levels. This makes "to maintain the body's fluid balance" the most accurate description of lymph's primary function.