here are three main lines of the Body's defensive mechanisms. nnate immunity, is termed as such because it is present at birth. t is always active, nonspecific, and rapid, and it works against a wide variety of pathogens, including parasitic vorms, protozoa, fungi, bacteria, and iruses. The first line of defense is nonspecific and part of our innate mmunity. It is chiefly composed of . The econd line is also part of the body's innate immunity. It is internal Ind is composed of Together, the first wo lines of defense are present at birth and thus part of innate mmunity. The third line is called adaptive immunity. are the main cells of the third line of lefense. Unlike the participants in the first and second lines of efense, lymphocytes respond against unique species and strains of athogens and alter the body's defenses such that specific and have nemory. Scientists call the third line of defense adaptive as the nmune system adapts itself to a specific pathogen. [Select] Lymphocytes external barriers and associated chemicals and processes protective cells, bloodborne chemicals, and processes that inactivate or kill invaders .