( ( The algae ) ( ( ( is continually ) ( ( making oxygen ) ( during ( ( the process ) ( of photosynthesis ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN algae)) (VP (VBZ is) (ADVP (RB continually)) (VP (VBG making) (NP (NN oxygen)) (PP (IN during) (NP (NP (DT the) (NN process)) (PP (IN of) (NP (NN photosynthesis))))))) (. .)))
The algae is continually making oxygen during the process of photosynthesis.
(ROOT (S (NP (NNP Oxygen)) (VP (VBZ is) (VP (VBN made) (PP (IN by) (NP (NP (NNS trees)) (CC and) (NP (JJ other) (NNS plants)))) (PP (IN during) (NP (NN photosynthesis))))) (. .)))