( There ( ( are ( ( two causes ) ( for ( ( the changes ) ( of seasons ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (CD two) (NNS causes)) (PP (IN for) (NP (NP (DT the) (NNS changes)) (PP (IN of) (NP (NNS seasons))))))) (. .)))
There are two causes for the changes of 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.