( ( This change ) ( ( causes ( the seasons ) ) . ) )
(ROOT (S (NP (DT This) (NN change)) (VP (VBZ causes) (NP (DT the) (NNS seasons))) (. .)))
This change causes the seasons.
(ROOT (S (NP (NP (DT A) (NN change)) (PP (IN of) (NP (NP (NN season)) (CC and) (NP (JJR less) (NN food))))) (ADVP (RB usually)) (VP (VB cause) (S (NP (JJ certain) (NNS animals)) (VP (TO to) (VP (VB migrate))))) (. .)))
A change of season and less food usually cause certain animals to migrate.