( ( Visible light ) ( ( is ( that ( it ( ( is ( ( the ( only part ) ) ( of ( the ( electromagnetic spectrum ) ) ) ) ) ( that ( ( our ( unaided eyes ) ) ( can see ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (JJ Visible) (NN light)) (VP (VBZ is) (SBAR (IN that) (S (NP (PRP it)) (VP (VBZ is) (NP (NP (DT the) (JJ only) (NN part)) (PP (IN of) (NP (DT the) (JJ electromagnetic) (NN spectrum)))) (SBAR (IN that) (S (NP (PRP$ our) (JJ unaided) (NNS eyes)) (VP (MD can) (VP (VB see))))))))) (. .)))
Visible light is that it is the only part of the electromagnetic spectrum that our unaided eyes can see.
(ROOT (S (NP (PRP We)) (VP (VBP call) (NP (DT the) (JJ only) (NN light)) (SBAR (IN that) (S (NP (NNS people)) (VP (MD can) (VP (VB see) (NP (JJ visible) (NN light))))))) (. .)))