( ( The population ) ( ( kept ( ( growing and ) growing ) ) . ) )
(ROOT (S (NP (DT The) (NN population)) (VP (VBD kept) (S (VP (VBG growing) (CC and) (VBG growing)))) (. .)))
The population kept growing and growing.
(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)) (. .)))