Subject	sedimentary rock layer
Predicate	be used by
Object	scientists
Modality	Modality Occurrences
Polarity	POSITIVE
Plausibility	0.0232
Neighborhood Sigma	0.0296
Local Sigma	0.0265
Example Sentences	Sentence Occurrences Source sedimentary rock layers are used by scientists to learn about the past 2 Google Autocomplete, Answers.com Questions