What is the primary function of immunoglobulins in the body?

Immunoglobulins, commonly known as antibodies, play a crucial role in the immune system by providing the body's defense against pathogens such as bacteria, viruses, and other foreign substances. Their primary function is to recognize and bind to specific antigens present on these invaders, marking them for destruction by other immune cells or neutralizing their harmful effects directly. This process is vital for the protection of the body and is an essential part of both the innate and adaptive immune responses.

In contrast, the other options depict functions unrelated to immunoglobulins. Transporting oxygen is primarily carried out by hemoglobin in red blood cells, while digestion is facilitated by enzymes secreted in the digestive tract. Enzymes themselves are proteins that assist in chemical processes throughout the body but do not serve the immune protective functions that immunoglobulins provide. Hence, the role of immunoglobulins in mounting an immune response fundamentally distinguishes them from other proteins and substances in the body.