( ( ( The ( lowest frequency ) ) ( electromagnetic waves ) ) ( ( are ( radio waves ) ) . ) )
(ROOT (S (NP (NP (DT The) (JJS lowest) (NN frequency)) (NP (JJ electromagnetic) (NNS waves))) (VP (VBP are) (NP (NN radio) (NNS waves))) (. .)))
The lowest frequency electromagnetic waves are radio waves.
(ROOT (S (NP (NNP Am) (NN radio) (NNS waves)) (VP (VBP exist) (PRT (RP in)) (NP (DT the) (ADJP (QP (CD 540) (TO to) (CD 1600))) (NN khz) (NN frequency) (NN range))) (. .)))