( ( Growing food ) . )
(ROOT (NP (NP (VBG Growing)) (NP (NN food)) (. .)))
Growing food.
(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)) (. .)))