( ( Natural selection ) ( ( ( is ( the idea ) ) ( that ( ( ( the ( individual organisms ) ) ( with ( traits ( ( most favorable ) ( to ( a ( given environment ) ) ) ) ) ) ) ( will ( be ( able ( to ( ( survive and ) reproduce ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Natural) (NN selection)) (VP (VBZ is) (NP (DT the) (NN idea)) (SBAR (IN that) (S (NP (NP (DT the) (JJ individual) (NNS organisms)) (PP (IN with) (NP (NP (NNS traits)) (ADJP (ADJP (RBS most) (JJ favorable)) (PP (TO to) (NP (DT a) (VBN given) (NN environment))))))) (VP (MD will) (VP (VB be) (ADJP (JJ able) (S (VP (TO to) (VP (VB survive) (CC and) (VB reproduce)))))))))) (. .)))
Natural selection is the idea that the individual organisms with traits most favorable to a given environment will  be able to survive and reproduce.
(ROOT (S (NP (JJ Natural) (NN selection)) (VP (VBZ is) (NP (NP (DT the) (NN process)) (SBAR (WHNP (WDT that)) (S (VP (VBZ allows) (NP (NNS organisms)) (PP (IN with) (NP (JJR better) (NNS traits) (S (VP (TO to) (VP (VB survive) (CC and) (VB produce))))))))))) (. .)))