Final answer:
The complement system can indeed be activated by specific defenses (antibodies in the adaptive immune system) and nonspecific defenses (components of the innate immune system), confirming the statement as true.
Step-by-step explanation:
True, the complement system can be activated by both specific and nonspecific defenses. The complement system is a series of proteins that are continuously synthesized, primarily by liver cells, and are abundant in the blood serum. These proteins engage in a cascade of enzymatic reactions that enhance the body's ability to repel bacteria, dispose of antigens and damaged cells, and promote inflammation.
The classical pathway is one method of complement activation and is part of the adaptive immune response. This pathway involves the binding of antibodies to the surface of a pathogen, which in turn activates the complement system. There's also the alternative pathway, which is part of the innate immune response and is triggered by the pathogen surfaces without the need for antibodies. Both these pathways lead to a series of reactions that facilitate phagocytosis and lysis of the pathogen.