( But ( fundamentally ( , ( clouds ( ( ( occur ( in ( ( the ( Earth 's ) ) atmosphere ) ) ) ( because ( there ( are ( ( particles ( in ( ( the ( Earth 's ) ) atmosphere ) ) ) ( ( on which ) ( ( water vapor ) ( condenses ( to ( ( ( ( ( form ( water drops ) ) , ) freeze ) , ) ( form ice ) ) ) ) ) ) ) ) ) ) ) . ) ) ) ) )
(ROOT (S (CC But) (ADVP (RB fundamentally)) (, ,) (NP (NNS clouds)) (VP (VBP occur) (PP (IN in) (NP (NP (DT the) (NN Earth) (POS 's)) (NN atmosphere))) (SBAR (IN because) (S (NP (EX there)) (VP (VBP are) (NP (NP (NNS particles)) (PP (IN in) (NP (NP (DT the) (NN Earth) (POS 's)) (NN atmosphere))) (SBAR (WHPP (IN on) (WHNP (WDT which))) (S (NP (NN water) (NN vapor)) (VP (VBZ condenses) (S (VP (TO to) (VP (VP (VB form) (NP (NN water) (NNS drops))) (, ,) (VP (VB freeze)) (, ,) (VP (VB form) (NP (NN ice)))))))))))))) (. .)))
But fundamentally, clouds occur in the Earth's atmosphere because there are particles in the Earth's atmosphere on which water vapor condenses to form water drops, freeze, form ice.
(ROOT (S (NP (NP (JJS Most)) (PP (IN of) (NP (NP (DT the) (NN earth) (POS 's)) (NN freshwater)))) (VP (VBZ is) (PP (IN in) (NP (NP (DT the) (NN form)) (PP (IN of) (ADJP (JJ frozen)))))) (. .)))