( ( ( The temperature ) ( of ( the system ) ) ) ( ( is ( ( the ( average ( kinetic energy ) ) ) ( of ( its particles ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN temperature)) (PP (IN of) (NP (DT the) (NN system)))) (VP (VBZ is) (NP (NP (DT the) (JJ average) (JJ kinetic) (NN energy)) (PP (IN of) (NP (PRP$ its) (NNS particles))))) (. .)))
The temperature of the system is the average kinetic energy of its particles.
(ROOT (S (PP (IN In) (NP (NN physics))) (, ,) (NP (NN temperature)) (VP (VBZ is) (VP (VBN defined) (PP (IN as) (NP (NP (DT the) (JJ average) (JJ kinetic) (NN energy)) (PP (IN of) (NP (NP (DT the) (NNS particles)) (PP (IN in) (NP (DT an) (NN object))))))))) (. ?)))