( ( The ( thymus gland ) ) ( ( ( ( makes ( T cells ) ) and ) ( is ( ( the ( master gland ) ) ( of ( a ( healthy ( immune system ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NNS thymus) (NN gland)) (VP (VP (VBZ makes) (NP (NNP T) (NNS cells))) (CC and) (VP (VBZ is) (NP (NP (DT the) (NN master) (NN gland)) (PP (IN of) (NP (DT a) (JJ healthy) (JJ immune) (NN system)))))) (. .)))
The thymus gland makes T cells and is the master gland of a healthy immune system.
(ROOT (S (NP (DT The) (NNS thymus) (NN gland)) (VP (VBZ produces) (NP (NN t) (NNS cells))) (. .)))