( Pheromones ( ( are ( ( chemical substances ) ( ( produced ( by ( an animal ) ) ) ( to ( ( serve ( as ( ( a stimulus ) ( for ( behavioral responses ) ) ) ) ) ( to ( others ( of ( the ( same species ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Pheromones)) (VP (VBP are) (NP (NP (NN chemical) (NNS substances)) (VP (VBN produced) (PP (IN by) (NP (DT an) (NN animal))) (S (VP (TO to) (VP (VB serve) (PP (IN as) (NP (NP (DT a) (NN stimulus)) (PP (IN for) (NP (JJ behavioral) (NNS responses))))) (PP (TO to) (NP (NP (NNS others)) (PP (IN of) (NP (DT the) (JJ same) (NN species))))))))))) (. .)))
Pheromones are chemical substances produced by an animal to serve as a stimulus for behavioral responses to others of the same species.
(ROOT (S (NP (NNS Pheromones)) (VP (VBP are) (VP (VBN released) (PP (IN into) (NP (NP (DT the) (NN environment)) (PP (IN for) (NP (NP (NN communication)) (PP (IN between) (NP (NP (NNS animals)) (PP (IN of) (NP (DT the) (JJ same) (NN species))))))))))) (. .)))