( ( The ( prostate gland ) ) ( ( makes ( ( a fluid ) ( that ( is ( part ( of ( ( semen , ) ( ( the fluid ) ( that ( contains sperm ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN prostate) (NN gland)) (VP (VBZ makes) (NP (NP (DT a) (NN fluid)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (NP (NP (NN part)) (PP (IN of) (NP (NP (NN semen)) (, ,) (NP (NP (DT the) (NN fluid)) (SBAR (WHNP (WDT that)) (S (VP (VBZ contains) (NP (NN sperm)))))))))))))) (. .)))
The prostate gland makes a fluid that is part of semen, the fluid that contains sperm.
(ROOT (S (NP (DT The) (NN prostate) (NN gland)) (VP (VBZ secretes) (NP (NP (DT a) (NN fluid)) (SBAR (WHNP (WDT that)) (S (VP (VBZ mixes) (PP (IN with) (NP (NN sperm))) (S (VP (TO to) (VP (VB help) (NP (NN form) (NN semen)))))))))) (. .)))