( Prokaryotes ( ( are ( ( ( a type ) ( of organism ) ) ( that ( have ( cells ( which ( lack ( a nucleus ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Prokaryotes)) (VP (VBP are) (NP (NP (DT a) (NN type)) (PP (IN of) (NP (NN organism))) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (NP (NP (NNS cells)) (SBAR (WHNP (WDT which)) (S (VP (VBP lack) (NP (DT a) (NN nucleus))))))))))) (. .)))
Prokaryotes are a type of organism that have cells which lack a nucleus.
(ROOT (S (NP (DT A) (JJ single-celled) (NN prokaryotic)) (VP (VBZ is) (NP (DT a) (NNS bacteria))) (. .)))