Electrolysis Practice Exam

The correct choice highlights the key components that play a vital role in the body's defense mechanisms against infections. White blood cells, also known as leukocytes, are crucial for identifying and combating pathogens such as bacteria, viruses, and fungi. They are part of the immune system and can be further categorized into several types, each with specific functions in fighting off infections.

Body secretions, such as mucus and saliva, serve as barriers and contain antimicrobial properties that help to trap and neutralize pathogens before they can enter the body. Unbroken skin acts as a physical barrier, preventing pathogens from entering the body. Together, these elements work in concert to provide a multi-layered defense system, effectively enhancing the body's ability to protect itself from infections.

The other options listed do not encompass the full range of defensive mechanisms in the manner that the correct choice does. While platelets and plasma are important for blood clotting and transporting immune cells, they are not primarily defensive forces against infections. Red blood cells mainly function to transport oxygen and do not directly engage in immune responses. Enzymes and hormones have various roles in metabolism and regulation but do not specifically act as defense mechanisms against infections.