( ( In ( a ( chemical reaction ) ) ) ( , ( ( ( the substances ) ( that ( are produced ) ) ) ( ( are ( called ( the products ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (DT a) (NN chemical) (NN reaction))) (, ,) (NP (NP (DT the) (NNS substances)) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (VP (VBN produced)))))) (VP (VBP are) (VP (VBN called) (NP (DT the) (NNS products)))) (. .)))
In a chemical reaction, the substances that are produced are called the products .
(ROOT (S (NP (NP (NNS Substances)) (VP (VBN produced) (PP (IN by) (NP (DT a) (NN reaction))))) (VP (VBP are) (VP (VBN known) (PP (IN as) (NP (NNS products))))) (. .)))