( ( ( A ( great deal ) ) ( of evidence ) ) ( ( ( supports ( the hypothesis ) ) ( that ( ( ( chloroplasts and ) mitochondria ) ( evolved ( from ( ( free ( living microorganisms ) ) ( that ( ( ( merged ( their ( respective ( metabolic abilities ) ) ) ) ( with ( ( a ( large ( host cell ) ) ) ( in ( an ( intracellular ( symbiotic relationship ) ) ) ) ) ) ) ( ( ( more ( ( than two ) billion ) ) years ) ago ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (JJ great) (NN deal)) (PP (IN of) (NP (NN evidence)))) (VP (VBZ supports) (NP (DT the) (NNS hypothesis)) (SBAR (IN that) (S (NP (NNS chloroplasts) (CC and) (NNS mitochondria)) (VP (VBD evolved) (PP (IN from) (NP (NP (JJ free) (NN living) (NNS microorganisms)) (SBAR (WHNP (WDT that)) (S (VP (VBD merged) (NP (PRP$ their) (JJ respective) (JJ metabolic) (NNS abilities)) (PP (IN with) (NP (NP (DT a) (JJ large) (NN host) (NN cell)) (PP (IN in) (NP (DT an) (JJ intracellular) (JJ symbiotic) (NN relationship))))) (ADVP (NP (QP (JJR more) (IN than) (CD two) (CD billion)) (NNS years)) (RB ago))))))))))) (. .)))
A great deal of evidence supports the hypothesis that chloroplasts and mitochondria evolved from free living microorganisms that merged their respective metabolic abilities with a large host cell in an intracellular symbiotic relationship more than two billion years ago.
(ROOT (S (NP (DT The) (JJ first) (VBG living) (NNS cells)) (VP (MD may) (VP (VB have) (VP (VBN evolved) (ADVP (NP (QP (RB around) (CD 4) (CD billion)) (NNS years)) (RB ago))))) (. .)))