( ( ( The ( critical amount ) ) ( of ( energy ( to ( make ( ( the reaction ) proceed ) ) ) ) ) ) ( ( is ( called ( the ( Activation Energy ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJ critical) (NN amount)) (PP (IN of) (NP (NN energy) (S (VP (TO to) (VP (VB make) (S (NP (DT the) (NN reaction)) (VP (VB proceed))))))))) (VP (VBZ is) (VP (VBN called) (NP (DT the) (NNP Activation) (NNP Energy)))) (. .)))
The critical amount of energy to make the reaction proceed is called the Activation Energy.
(ROOT (S (NP (NP (DT The) (NN amount)) (PP (IN of) (NP (NP (NN energy)) (VP (VBN required) (S (VP (TO to) (VP (VB begin) (NP (DT a) (JJ chemical) (NN reaction))))))))) (VP (VBZ is) (VP (VBN known) (PP (IN as) (NP (DT the) (NN activation) (NN energy))))) (. .)))