( ( A calorie ) ( ( is ( ( a unit ) ( of ( heat ( ( used ( for energy ) ) ( for ( ( our body ) ( s ( ( metabolism ( , ( or ( simply , ) ) ) ) ( how ( ( our body ) ( ( burns food ) ( to ( get energy ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (NN calorie)) (VP (VBZ is) (NP (NP (DT a) (NN unit)) (PP (IN of) (NP (NP (NN heat)) (VP (VBN used) (PP (IN for) (NP (NN energy))) (SBAR (IN for) (S (NP (PRP$ our) (NN body)) (VP (VBZ s) (ADJP (JJ metabolism) (PRN (, ,) (CC or) (ADVP (RB simply)) (, ,)) (SBAR (WHADVP (WRB how)) (S (NP (PRP$ our) (NN body)) (VP (VBZ burns) (NP (NN food)) (S (VP (TO to) (VP (VB get) (NP (NN energy))))))))))))))))) (. .)))
A calorie is a unit of heat used for energy for our body s metabolism, or simply, how our body burns food to get energy.
(ROOT (S (NP (DT A) (NN calorie)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB express) (NP (NP (DT the) (NN amount)) (PP (IN of) (NP (NN energy)))) (PP (IN in) (NP (NN food)))))))) (. .)))
A calorie is used to express the amount of energy in food.