( Secretions ( ( ( may also ) ( include ( ( pheromones , ) ( which ( are ( substances ( ( ( ( released ( by ( ( the glands ) ( of ( some animals ) ) ) ) ) ( into ( ( ( the ( external environment ) ) , ) ( where ( they ( serve ( to ( ( regulate or ) ( sexually ( attract ( ( other individuals ) ( of ( the ( same species ) ) ) ) ) ) ) ) ) ) ) ) ) ) and ) ( sometimes ( of ( other species ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Secretions)) (VP (MD may) (ADVP (RB also)) (VP (VB include) (NP (NP (NNS pheromones)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBP are) (NP (NP (NNS substances)) (RRC (RRC (VP (VBN released) (PP (IN by) (NP (NP (DT the) (NNS glands)) (PP (IN of) (NP (DT some) (NNS animals))))) (PP (IN into) (NP (NP (DT the) (JJ external) (NN environment)) (, ,) (SBAR (WHADVP (WRB where)) (S (NP (PRP they)) (VP (VBP serve) (S (VP (TO to) (VP (VP (VB regulate)) (CC or) (VP (ADVP (RB sexually)) (VB attract) (NP (NP (JJ other) (NNS individuals)) (PP (IN of) (NP (DT the) (JJ same) (NN species))))))))))))))) (CC and) (RRC (ADVP (RB sometimes)) (PP (IN of) (NP (JJ other) (NNS species)))))))))))) (. .)))
Secretions may also include pheromones, which are substances released by the glands of some animals into the external environment, where they serve to regulate or sexually attract other individuals of the same species and sometimes of other 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))))))))))) (. .)))