What is the primary function of the lymphatic system?

The primary function of the lymphatic system is to filter out organisms that cause disease, which is accurately represented by the choice provided. The lymphatic system plays a crucial role in the immune response by transporting lymph, a fluid containing infection-fighting white blood cells, throughout the body. This system includes lymph nodes, which act as filters that trap pathogens and foreign substances, preventing them from spreading. The lymphatic vessels carry lymph fluid that collects waste products, bacteria, and toxins, ensuring they are processed and eliminated effectively.

This filtering function is vital for maintaining the body’s health and preventing infections, as the lymphatic system helps initiate immune responses when pathogens are detected. Additionally, it contributes to the overall maintenance of fluid balance in the body and the absorption of fats from the digestive tract.

The other functions mentioned in the incorrect options are not the primary functions of the lymphatic system. For instance, transporting oxygen in the blood is predominantly the responsibility of the circulatory system, not the lymphatic system. Hormonal control is managed through the endocrine system, and while muscle contractions are influenced by the nervous and muscular systems, they are not relevant to the lymphatic system's primary role.