Subject	gas exchange
Predicate	be more difficult than
Object	than terrestrial animals with lungs
Modality	Modality Occurrences
Polarity	POSITIVE
Plausibility	0.0017
Neighborhood Sigma	0.0018
Local Sigma	1.0000
Example Sentences	Sentence Occurrences Source gas exchange is more difficult for aquatic animals with gills than for terrestrial animals with lungs 1 Answers.com Questions