TOEFL Reading: ETS-TOEFL阅读机经 - V1T7545Z1N3AX3S4L$

main idea. A. The ability of some unicellular organisms to detect light and change their behavior accordingly suggests that eyes did not originate with multicellular animals. B. The earliest eyes apparently contained molecules that were capable of forming and focusing images. C. Too few fossils from the Precambrian have been found to determine which if any Precambrian organisms had eyes. D. Evidence from the Burgess Shale suggests that eyes of some early animals were similar to the eyes of living crustaceans. E. Fossil evidence suggests that organisms in the Burgess Shale with faceted eyes developed later than organisms in the Burgess Shale with nonfaceted eyes. F. The large size and possible complexity of the eyes of some organisms in the Burgess Shale suggest that their eyes were not the first eyes.