( ( The ( human brain ) ) ( ( is ( by ( ( far ( the ( most ( mysterious organ ) ) ) ) ( in ( the body ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ human) (NN brain)) (VP (VBZ is) (PP (IN by) (NP (NP (RB far) (DT the) (JJS most) (JJ mysterious) (NN organ)) (PP (IN in) (NP (DT the) (NN body)))))) (. .)))
The human brain is by far the most mysterious organ in the body.
(ROOT (S (NP (DT The) (NN brain)) (VP (VBZ is) (NP (NP (DT the) (ADJP (RBS most) (JJ complex)) (NN organ)) (PP (IN in) (NP (DT the) (JJ human) (NN body))))) (. .)))