( It ( ( is ( measured ( from ( ( ( absolute zero ) , ) ( ( the ( theoretical temperature ) ) ( ( at which ) ( ( all ( molecular activity ) ) ( nearly ceases ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (VP (VBN measured) (PP (IN from) (NP (NP (JJ absolute) (NN zero)) (, ,) (NP (NP (DT the) (JJ theoretical) (NN temperature)) (SBAR (WHPP (IN at) (WHNP (WDT which))) (S (NP (DT all) (JJ molecular) (NN activity)) (ADVP (RB nearly)) (VP (VBZ ceases))))))))) (. .)))
It is measured from absolute zero, the theoretical temperature at which all molecular activity nearly ceases.
(ROOT (S (NP (NP (DT The) (NN temperature)) (SBAR (WHPP (IN at) (WHNP (WDT which))) (S (NP (DT all) (JJ molecular) (NN motion)) (VP (VBZ has) (VP (VBN ceased)))))) (VP (VBZ is) (VP (VBN called) (NP (JJ absolute) (NN zero)))) (. .)))