( ( ( Most ecosystems ) ( on Earth ) ) ( ( ( ( derive ( their energy ) ) ( either ( ( directly or ) indirectly ) ) ) ( through ( ( ( the Sun ) and ) ( ( the process ) ( of photosynthesis ) ) ) ) ) . ) )
(ROOT (S (NP (NP (JJS Most) (NNS ecosystems)) (PP (IN on) (NP (NNP Earth)))) (VP (VBD derive) (NP (PRP$ their) (NN energy)) (ADVP (CC either) (RB directly) (CC or) (RB indirectly)) (PP (IN through) (NP (NP (DT the) (NNP Sun)) (CC and) (NP (NP (DT the) (NN process)) (PP (IN of) (NP (NN photosynthesis))))))) (. .)))
Most ecosystems on Earth derive their energy either directly or indirectly through the Sun and the process of photosynthesis.
(ROOT (S (NP (NP (JJS Most)) (PP (IN of) (NP (NP (DT the) (NN energy)) (VP (VBN used) (PP (IN by) (NP (VBG living) (NNS things))))))) (VP (VBZ comes) (ADVP (CC either) (RB directly) (CC or) (RB indirectly)) (PP (IN from) (NP (DT the) (NN sun)))) (. .)))
Most of the energy used by living things comes either directly or indirectly from the sun.