( Dieldrin ( ( is ( highly ( toxic ( to ( ( ( ( ( ( fish and ) ( other ( aquatic animals ) ) ) , ) ( particularly frogs ) ) , ) ( whose ( embryos ( can ( ( ( develop ( spinal deformities ) ) ( after exposure ) ) ( to ( low levels ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Dieldrin)) (VP (VBZ is) (ADJP (RB highly) (JJ toxic) (PP (TO to) (NP (NP (NN fish)) (CC and) (NP (JJ other) (JJ aquatic) (NNS animals)) (, ,) (ADJP (RB particularly) (JJ frogs)) (, ,) (SBAR (WP$ whose) (S (NP (NNS embryos)) (VP (MD can) (VP (VB develop) (NP (JJ spinal) (NNS deformities)) (PP (IN after) (NP (NN exposure))) (PP (TO to) (NP (JJ low) (NNS levels))))))))))) (. .)))
Dieldrin is highly toxic to fish and other aquatic animals, particularly frogs, whose embryos can develop spinal deformities after exposure to low levels.
(ROOT (S (NP (NP (NNS Invertebrates)) (-LRB- -LRB-) (CC and) (NP (JJR higher) (NNS animals)) (-RRB- -RRB-)) (VP (MD can) (ADVP (RB also)) (VP (VB be) (VP (VBN placed) (PP (IN in) (NP (NP (CD one)) (PP (IN of) (NP (CD two) (NNS groups))))) (PP (VBN based) (PP (IN on) (SBAR (WHADVP (WRB how)) (S (NP (PRP they)) (VP (VBP develop) (PP (IN as) (NP (NNS embryos))))))))))) (. .)))
Invertebrates (and higher animals) can also be placed in one of two groups based on how they develop as embryos.