Assertion: eye's cone | /r/CapableOf | operate in good lighting conditions
Facets:
Source sentences:
text: Although the tight circle of cones in each eye gives man his ability to do close, detailed work (including reading) and to discriminate colors, the cones are virtually useless in detecting objects that are a bit off center from our direct focus, and furthermore operate only in good lighting conditions or in response to bright light sources.