( ( The ( bacterium ( Borrelia burgdorferi ) ) ) ( ( causes ( ( Lyme ( disease ( and ( deer ticks ) ) ) ) ( ( transmit it ) ( when ( they bite ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN bacterium) (NNP Borrelia) (NN burgdorferi)) (VP (VBZ causes) (S (NP (NNP Lyme) (NN disease) (CC and) (NNS deer) (NNS ticks)) (VP (VB transmit) (NP (PRP it)) (SBAR (WHADVP (WRB when)) (S (NP (PRP they)) (VP (VB bite))))))) (. .)))
The bacterium Borrelia burgdorferi causes Lyme disease and deer ticks transmit it when they bite.
(ROOT (S (NP (JJ Lyme) (NN disease)) (VP (VBZ is) (VP (VBN caused) (PP (IN by) (NP (NNS bacteria))))) (. .)))
Lyme disease is caused by bacteria.