( and ( ( ( ( its period ) , ) ( which ( is ( the time ) ) ) ) ( ( ( required ( for ( the wave ) ) ) ( to ( pass ( a ( fixed point ) ) ) ) ) . ) ) )
(ROOT (S (CC and) (NP (NP (PRP$ its) (NN period)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (DT the) (NN time)))))) (VP (VBD required) (PP (IN for) (NP (DT the) (NN wave))) (S (VP (TO to) (VP (VB pass) (NP (DT a) (VBN fixed) (NN point)))))) (. .)))
and its period, which is the time required for the wave to pass a fixed point.
(ROOT (S (NP (NN Period)) (VP (VBZ is) (NP (NP (DT the) (NN time) (NN interval)) (VP (VBN required) (PP (IN for) (NP (CD one) (JJ complete) (NN wave) (S (VP (TO to) (VP (VB pass) (NP (NP (DT a) (NN point)) (VP (VBN called))))))))))) (. .)))