What is the primary function of leukocytes in the body?

The primary function of leukocytes, or white blood cells, is to help the body defend against diseases and foreign materials. Leukocytes are an essential component of the immune system, playing a crucial role in identifying, targeting, and eliminating pathogens such as bacteria, viruses, and fungi. They are involved in various immune responses, including inflammation, phagocytosis (where certain leukocytes engulf and destroy invading organisms), and the production of antibodies that neutralize harmful agents.

This function is vital for maintaining the body's health and preventing infections. By recognizing and responding to foreign substances, leukocytes contribute to the overall defense mechanisms that protect the body from external threats. Their ability to adapt and remember previous encounters with pathogens is also important for long-term immunity.

The other options, while they describe important biological functions, do not pertain to leukocytes. Hormone production is primarily the function of endocrine glands, oxygen transport occurs mainly through red blood cells, and nutrient storage for energy is managed by various tissues, including muscle and adipose tissue.