( ( In essence ) ( , ( it ( ( s ( ( a ( small-scale ( power plant ) ) ) ( that ( generates ( electricity ( ( using oxygen ) ( from ( ( ( the air ) and ) ( ( any ( fuel source ) ) ( that ( contains ( ( hydrogen , ) ( such ( as ( natural ( ( gas or ) propane ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (PP (IN In) (NP (NN essence))) (, ,) (NP (PRP it)) (VP (VBZ s) (NP (NP (DT a) (JJ small-scale) (NN power) (NN plant)) (SBAR (WHNP (WDT that)) (S (VP (VBZ generates) (NP (NP (NN electricity)) (VP (VBG using) (NP (NN oxygen)) (PP (IN from) (NP (NP (DT the) (NN air)) (CC and) (NP (NP (DT any) (NN fuel) (NN source)) (SBAR (WHNP (WDT that)) (S (VP (VBZ contains) (NP (NP (NN hydrogen)) (, ,) (PP (JJ such) (IN as) (NP (JJ natural) (NN gas) (CC or) (NN propane))))))))))))))))) (. .)))
In essence, it s a small-scale power plant that generates electricity using oxygen from the air and any fuel source that contains hydrogen, such as natural gas or propane.
(ROOT (S (PP (IN On) (NP (DT a) (JJ global) (NN scale))) (, ,) (NP (NP (NNS plants)) (CC and) (NP (JJ other) (JJ photosynthetic) (NNS organisms))) (VP (VBP have) (VP (VBN generated) (NP (NP (DT all)) (PP (IN of) (NP (NP (DT the) (NN oxygen)) (PP (IN in) (NP (DT the) (NN air)))))))) (. .)))
On a global scale, plants and other photosynthetic organisms have generated all of the oxygen in the air.