( ( Most arthropods ) ( ( ( ( reproduce sexually ) , ) ( through ( internal fertilization ) ) ) . ) )
(ROOT (S (NP (JJS Most) (NNS arthropods)) (VP (VB reproduce) (ADVP (RB sexually)) (, ,) (PP (IN through) (NP (JJ internal) (NN fertilization)))) (. .)))
Most arthropods reproduce sexually, through internal fertilization.
(ROOT (S (NP (NNS Amphibians)) (ADVP (RB sexually)) (VP (VB reproduce) (PP (IN through) (NP (JJ external) (CC or) (JJ internal) (NN fertilization)))) (. .)))