( ( stem cells ) ( ( Cells ( in ( ( bone marrow ) ( that ( ( produce lymphocytes ) ( by ( mitotic division ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NN stem) (NNS cells)) (VP (VBZ Cells) (PP (IN in) (NP (NP (NN bone) (NN marrow)) (SBAR (WHNP (WDT that)) (S (VP (VBP produce) (NP (NNS lymphocytes)) (PP (IN by) (NP (JJ mitotic) (NN division))))))))) (. .)))
stem cells  Cells in bone marrow that produce lymphocytes by mitotic division.
(ROOT (S (NP (NNP Bone) (NNP marrow)) (VP (VP (VBZ is) (VP (VBN found) (PP (IN inside) (NP (JJ many) (NNS bones))))) (CC and) (VP (VBZ produces) (NP (NNS lymphocytes)))) (. .)))