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Impressions of tropical swamp plants were observed on rocks in polar regions. The impressions were dark black imprints, which means the fossils are examples of . The fossils tell us that polar regions .

Light from two different sources are incident upon the same side of a polarizing filter. light from one source is polarized with total intensity ip, while light from the other source is unpolarized with total intensity iu. as you rotate the polarizing filter through 360 degrees, the intensity of the transmitted light on the other side varies by a factor of 9. what is the relative intensity of the initial polarized source to the unpolarized source, or ip/iu?