( ( ( ( Change ( ( the polarity ) ( of ( the current ) ) ) ) and ) ( observe ( ( the behavior ) ( of ( the protists ) ) ) ) ) . )
(ROOT (S (VP (VP (VB Change) (NP (NP (DT the) (NN polarity)) (PP (IN of) (NP (DT the) (JJ current))))) (CC and) (VP (VB observe) (NP (NP (DT the) (NN behavior)) (PP (IN of) (NP (DT the) (NNS protists)))))) (. .)))
Change the polarity of the current and observe the behavior of the protists.
(ROOT (S (NP (JJ Multiple) (NN fission)) (VP (VBZ is) (ADVP (RBR more) (RB often)) (VP (VBN observed) (PP (IN among) (NP (NNS protists))))) (. .)))