( It ( ( is ( a ( growing population ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (NP (DT a) (VBG growing) (NN population))) (. .)))
It is 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)) (. .)))