( ( ( The energy ) ( that ( ( most ( living things ) ) ( need ( to survive ) ) ) ) ) ( ( ( comes ( from ( the Sun ) ) ) ( in ( ( the form ) ( of ( ( light and ) heat ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN energy)) (SBAR (IN that) (S (NP (JJS most) (NN living) (NNS things)) (VP (VBP need) (S (VP (TO to) (VP (VB survive)))))))) (VP (VBZ comes) (PP (IN from) (NP (DT the) (NNP Sun))) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (NP (NN light) (CC and) (NN heat)))))) (. .)))
The energy that most living things need to survive comes from the Sun in the    form of light and heat.
(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.