( ( ( ( ( ( ( The amount ) ( of ( O 2 ) ) ) ( in ( the atmosphere ) ) ) ( has ( changed ( over time ) ) ) ) : ) ( ( give ( the evidence ) ) ( from ( ( the ( geologic record ) ) ( that ( shows ( this ( -LRB- ( ( ( ( and about ) what ) ( time ( ( the change ) occurs ) ) ) -RRB- ) ) ) ) ) ) ) ) ) . )
(ROOT (S (S (NP (NP (DT The) (NN amount)) (PP (IN of) (NP (NNP O) (CD 2))) (PP (IN in) (NP (DT the) (NN atmosphere)))) (VP (VBZ has) (VP (VBN changed) (PP (IN over) (NP (NN time)))))) (: :) (S (VP (VB give) (NP (DT the) (NN evidence)) (PP (IN from) (NP (NP (DT the) (JJ geologic) (NN record)) (SBAR (WHNP (WDT that)) (S (VP (VBZ shows) (NP (NP (DT this)) (PRN (-LRB- -LRB-) (SBAR (WHNP (QP (CC and) (RB about)) (WP what)) (S (NP (NN time)) (NP (DT the) (NN change)) (VP (VBZ occurs)))) (-RRB- -RRB-)))))))))) (. .)))
The amount of O 2 in the atmosphere has changed over time: give the evidence from the geologic record that shows this (and about what time the change occurs).
(ROOT (S (SBAR (WHADVP (WRB How)) (S (NP (NN ice) (NNS cores)) (VP (VBP are) (ADJP (JJ important) (PP (TO to) (NP (NP (DT the) (NN study)) (PP (IN of) (NP (JJ geologic) (NN history))))))))) (VP (VBZ is) (ADVP (RBS best)) (VP (VBN described) (SBAR (IN as) (S (NP (PRP they)) (VP (VBP contain) (NP (NN evidence) (NN showing) (NNS changes)) (PP (IN in) (NP (NP (DT the) (JJ atmospheric) (NN composition)) (PP (IN over) (NP (NN time)))))))))) (. .)))