( ( Waves ( that ( require ( a medium ) ) ) ) ( ( are ( called ( ( ( mechanical waves ) ( -LRB- ( ( answer B. ) -RRB- ) ) ) 10 ) ) ) . ) )
(ROOT (S (NP (NP (NNS Waves)) (SBAR (WHNP (WDT that)) (S (VP (VBP require) (NP (DT a) (NN medium)))))) (VP (VBP are) (VP (VBN called) (NP (NP (JJ mechanical) (NNS waves)) (PRN (-LRB- -LRB-) (NP (NNP answer) (NNP B.)) (-RRB- -RRB-)) (ADJP (CD 10))))) (. .)))
Waves that require a medium are called mechanical waves (answer B.) 10.
(ROOT (S (NP (JJ Mechanical) (NNS waves)) (VP (VBP require) (NP (NP (DT a) (NN material) (NN medium)) (PP (JJ such) (IN as) (NP (NP (NN water)) (, ,) (NP (NN air)) (, ,) (CC or) (NP (NN rope)))))) (. .)))