( ( ( ( Spiders ( reproduce sexually ) ) and ) ( fertilization ( is ( ( internal but ) indirect ) ) ) ) . )
(ROOT (S (S (NP (NNS Spiders)) (VP (VB reproduce) (ADVP (RB sexually)))) (CC and) (S (NP (NN fertilization)) (VP (VBZ is) (ADJP (JJ internal) (CC but) (NN indirect)))) (. .)))
Spiders reproduce sexually and fertilization is internal but indirect.
(ROOT (S (NP (NNS Amphibians)) (ADVP (RB sexually)) (VP (VB reproduce) (PP (IN through) (NP (JJ external) (CC or) (JJ internal) (NN fertilization)))) (. .)))