She will first analyze the historical data by separating the causes of past changes in demand into the following  (1) trend, (2) seasonality, (3) cyclicality, and (4) random fluctuation.
( She ( ( ( will first ) ( analyze ( ( ( ( ( ( the ( historical data ) ) ( by ( ( separating ( ( the causes ) ( of ( ( past changes ) ( in demand ) ) ) ) ) ( into ( ( ( ( the ( ( ( ( following ( ( -LRB- ( 1 -RRB- ) ) trend ) ) , ) ( -LRB- ( 2 -RRB- ) ) ) seasonality ) ) , ) ( -LRB- ( 3 -RRB- ) ) ) cyclicality ) ) ) ) ) , ) and ) ( -LRB- ( 4 -RRB- ) ) ) ( random fluctuation ) ) ) ) . ) )
(ROOT (S (NP (PRP She)) (VP (MD will) (ADVP (RB first)) (VP (VB analyze) (NP (NP (NP (DT the) (JJ historical) (NNS data)) (PP (IN by) (S (VP (VBG separating) (NP (NP (DT the) (NNS causes)) (PP (IN of) (NP (NP (JJ past) (NNS changes)) (PP (IN in) (NP (NN demand)))))) (PP (IN into) (NP (NP (NP (DT the) (NP (NP (JJ following) (PRN (-LRB- -LRB-) (NP (CD 1)) (-RRB- -RRB-)) (NN trend)) (, ,) (PRN (-LRB- -LRB-) (NP (CD 2)) (-RRB- -RRB-))) (NN seasonality)) (, ,) (PRN (-LRB- -LRB-) (NP (CD 3)) (-RRB- -RRB-))) (ADVP (RB cyclicality)))))))) (, ,) (CC and) (PRN (-LRB- -LRB-) (NP (CD 4)) (-RRB- -RRB-)) (NP (JJ random) (NN fluctuation))))) (. .)))
Seasonality is considered to be one of the causes of variations in demand.
( Seasonality ( ( is ( considered ( to ( be ( one ( of ( ( the causes ) ( of ( variations ( in demand ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Seasonality)) (VP (VBZ is) (VP (VBN considered) (S (VP (TO to) (VP (VB be) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT the) (NNS causes)) (PP (IN of) (NP (NP (NNS variations)) (PP (IN in) (NP (NN demand))))))))))))) (. .)))