( ( ( Other species ) ( of animals ) ) ( ( have ( hormones ( that ( are ( similar ( to ( ( but ( not ( exact ( in structure ) ) ) ) ( to ( human hormones ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJ Other) (NNS species)) (PP (IN of) (NP (NNS animals)))) (VP (VBP have) (NP (NP (NNS hormones)) (SBAR (WHNP (WDT that)) (S (VP (VBP are) (ADJP (JJ similar) (PP (TO to) (ADJP (ADJP (CC but) (RB not) (JJ exact) (PP (IN in) (NP (NN structure)))) (PP (TO to) (NP (JJ human) (NNS hormones))))))))))) (. .)))
Other species of animals have hormones that are similar to but not exact in structure to human hormones.
(ROOT (S (NP (NP (DT The) (NN conclusion)) (SBAR (IN that) (S (NP (CD two) (NN animal) (NNS species)) (VP (VBD evolved) (PP (IN from) (NP (DT a) (JJ common) (NN ancestor))) (PP (IN in) (NP (JJ recent) (JJ geological) (NN history))))))) (VP (VBZ is) (ADVP (RBS best)) (VP (VBN supported) (PP (IN by) (NP (DT the) (NN observation))) (SBAR (IN that) (S (NP (DT the) (NNS species)) (VP (VBP have) (NP (JJ similar) (NN bone) (NN structure))))))) (. .)))
The conclusion that two animal species evolved from a common ancestor in recent geological history is best supported by the observation that the species have similar bone structure.