( ( a ( growing population ) ) ; )
(ROOT (NP (NP (DT a) (JJ growing) (NN population)) (: ;)))
a growing population;
(ROOT (S (SBAR (IN As) (S (NP (DT the) (NN population)) (VP (VBZ grows)))) (, ,) (NP (NP (NN competition)) (PP (IN for) (NP (NN food)))) (VP (VBZ grows)) (. .)))