( ( The ( internal energy ) ) ( ( ( consists ( of ( both ( the ( kinetic ( and ( potential energy ) ) ) ) ) ) ) ( of ( the ( trapped molecules ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ internal) (NN energy)) (VP (VBZ consists) (PP (IN of) (NP (PDT both) (DT the) (JJ kinetic) (CC and) (JJ potential) (NN energy))) (PP (IN of) (NP (DT the) (JJ trapped) (NNS molecules)))) (. .)))
The internal energy consists of both the kinetic and potential energy of the trapped molecules.
(ROOT (S (NP (NP (DT The) (NN sum)) (PP (IN of) (NP (NP (DT the) (JJ kinetic) (CC and) (JJ potential) (NNS energies)) (PP (IN of) (NP (NP (DT a) (NN system) (POS 's)) (NNS atoms) (CC and) (NNS molecules)))))) (VP (VBZ is) (VP (VBN called) (NP (JJ internal) (NN energy)))) (. .)))