( ( ( ( ( ( The cytoplasm ) ( -LRB- ( ( arrow heads ) -RRB- ) ) ) or ) ( ( the surface ) ( of ( vacuolated cells ) ) ) ) ( -LRB- ( arrows -RRB- ) ) ) ( ( ( more often ) ( reveals ( positive reaction ) ) ) . ) )
(ROOT (S (NP (NP (NP (NP (DT The) (NN cytoplasm)) (PRN (-LRB- -LRB-) (NP (NN arrow) (NNS heads)) (-RRB- -RRB-))) (CC or) (NP (NP (DT the) (NN surface)) (PP (IN of) (NP (JJ vacuolated) (NNS cells))))) (PRN (-LRB- -LRB-) (NP (NNS arrows)) (-RRB- -RRB-))) (VP (ADVP (RBR more) (RB often)) (VBZ reveals) (NP (JJ positive) (NN reaction))) (. .)))
The cytoplasm (arrow heads) or the surface of vacuolated cells (arrows) more often reveals positive reaction.
(ROOT (S (NP (JJ Reversible) (NNS reactions)) (VP (VBP are) (VP (VBN indicated) (PP (IN by) (NP (NP (JJ opposite-headed) (NNS kinds)) (PP (IN of) (NP (NNS arrows))))))) (. .)))
Reversible reactions are indicated by opposite-headed kinds of arrows.