( ( ( ( ( ( Each species ) ( has ( ( an ( average ( body size ) ) ) ( that ( ( works well ) ( in ( its environment ) ) ) ) ) ) ) , ) and ) ( ( ( ( ( ( the ( body 's ) ) organs ) , ) ( such ( as ( ( ( the lungs ) and ) heart ) ) ) ) , ) ( are ( designed ( to ( work ( best ( at ( that ( ( size and ) weight ) ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (DT Each) (NNS species)) (VP (VBZ has) (NP (NP (DT an) (JJ average) (NN body) (NN size)) (SBAR (WHNP (WDT that)) (S (VP (VBZ works) (ADVP (RB well)) (PP (IN in) (NP (PRP$ its) (NN environment))))))))) (, ,) (CC and) (S (NP (NP (NP (DT the) (NN body) (POS 's)) (NNS organs)) (, ,) (PP (JJ such) (IN as) (NP (NP (DT the) (NNS lungs)) (CC and) (NP (NN heart)))) (, ,)) (VP (VBP are) (VP (VBN designed) (S (VP (TO to) (VP (VB work) (NP (NP (JJS best)) (PP (IN at) (NP (DT that) (NN size) (CC and) (NN weight)))))))))) (. .)))
Each species has an average body size that works well in its environment, and the body's organs, such as the lungs and heart, are designed to work best at that size and weight.
(ROOT (S (PP (IN In) (NP (PRP$ your) (NN body))) (, ,) (NP (NP (DT the) (NN heart)) (CC and) (NP (NNS lungs))) (VP (VBP work) (ADVP (RB together)) (S (VP (TO to) (VP (VB make) (ADJP (JJ sure)) (SBAR (IN that) (S (NP (NN oxygen)) (VP (VBZ gets) (PP (TO to) (NP (NP (PDT all) (DT the) (JJ other) (NNS organs)) (PP (IN of) (NP (PRP$ your) (NN body)))))))))))) (. .)))
In your body, the heart and lungs work together to make sure that oxygen gets to all the other organs of your body.