( ( Since ( ( each antibody ) ( ( can only ) ( match ( one antigen ) ) ) ) ) ( , ( ( ( a ( diverse population ) ) ( of antibodies ) ) ( ( is ( necessary ( to ( guard ( against ( ( a variety ) ( of antigens ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (SBAR (IN Since) (S (NP (DT each) (NN antibody)) (VP (MD can) (ADVP (RB only)) (VP (VB match) (NP (CD one) (NN antigen)))))) (, ,) (NP (NP (DT a) (JJ diverse) (NN population)) (PP (IN of) (NP (NNS antibodies)))) (VP (VBZ is) (ADJP (JJ necessary) (S (VP (TO to) (VP (VB guard) (PP (IN against) (NP (NP (DT a) (NN variety)) (PP (IN of) (NP (NNS antigens)))))))))) (. .)))
Since each antibody can only match one antigen, a diverse population of antibodies is necessary to guard against a variety of antigens.
(ROOT (S (NP (DT An) (NN antibody)) (VP (MD can) (VP (VB match) (NP (NP (CD one) (NNS types)) (PP (IN of) (NP (NNS antigens)))))) (. .)))