( ( The crust ) ( ( is ( ( ( thicker and ) lighter ) ( at ( the ( ( ( ( ( continents and ) thinner ) and ) ( denser ( at ( the ocean ) ) ) ) floor ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN crust)) (VP (VBZ is) (NP (NP (JJR thicker) (CC and) (JJR lighter)) (PP (IN at) (NP (DT the) (ADJP (ADJP (JJ continents) (CC and) (JJR thinner)) (CC and) (ADJP (JJ denser) (PP (IN at) (NP (DT the) (NN ocean))))) (NN floor))))) (. .)))
The crust is thicker and lighter at the continents and thinner and denser at the ocean floor.
(ROOT (S (NP (NP (DT The) (NN creation) (CC and) (NN destruction)) (PP (IN of) (NP (JJ oceanic) (NN crust)))) (VP (VBZ is) (NP (DT the) (NN reason) (NN continents) (NN move))) (. .)))