( ( ( mere rotation ) ( of ( Earth ( on ( its ( own axis ) ) ) ) ) ) ( ( causes ( ( day and ) night ) ) . ) )
(ROOT (S (NP (NP (JJ mere) (NN rotation)) (PP (IN of) (NP (NP (NNP Earth)) (PP (IN on) (NP (PRP$ its) (JJ own) (NNS axis)))))) (VP (VBZ causes) (NP (NN day) (CC and) (NN night))) (. .)))
mere rotation of Earth on its own axis causes day and night.
(ROOT (S (NP (EX There)) (VP (VBP are) (NP (NP (QP (JJR fewer) (IN than) (CD 24)) (NNS hours)) (PP (IN of) (NP (NP (NN daylight)) (PP (IN in) (NP (NN alaska)))))) (PP (IN during) (NP (NP (DT each) (NN day)) (PP (IN in) (NP (NNP april))))) (SBAR (IN because) (S (NP (NP (NN earth) (POS 's)) (NN rotation)) (VP (VBZ causes) (NP (DT both) (NN day) (CC and) (NN night)))))) (. .)))