( ( Of ( ( the ( organic compounds ) ) ( with ( biological relevance ) ) ) ) ( , ( carbohydrates ( ( ( contain ( the ( largest proportion ) ) ) ( by ( mass ( of oxygen ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN Of) (NP (NP (DT the) (JJ organic) (NNS compounds)) (PP (IN with) (NP (JJ biological) (NN relevance))))) (, ,) (NP (NNS carbohydrates)) (VP (VBP contain) (NP (DT the) (JJS largest) (NN proportion)) (PP (IN by) (NP (NP (NN mass)) (PP (IN of) (NP (NN oxygen)))))) (. .)))
Of the organic compounds with biological relevance, carbohydrates contain the largest proportion by mass of oxygen.
(ROOT (S (NP (NNS Carbohydrates)) (VP (VBP are) (NP (NP (DT the) (ADJP (RBS most) (JJ common)) (NN type)) (PP (IN of) (NP (JJ organic) (NN compound))))) (. .)))