|Question 12Verbal

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Biologist Rosanna Alegado believes that we might learn how multicellular organisms developed from single-celled ones if we understand why the single-celled organism S. rosetta, the oldest living relative of animals, sometimes forms colonies of cells. Alegado and colleagues reviewed data from many studies about how S. rosetta responds when exposed to another type of single-celled organism, bacteria, including David C. Edman's work with Listeria monocytogenes bacteria and Jang-Cheon Cho's work with Croceibacter atlanticus bacteria. Alegado and colleagues concluded that neither L. monocytogenes nor C. atlanticus are likely to have played a significant role in the development of multicellular organisms.
Which finding, if true, would most directly support Alegado and colleagues' conclusion?
S. rosetta did not tend to form colonies when exposed to either L. monocytogenes or C. atlanticus.
A
S. rosetta tended to form colonies when exposed to L. monocytogenes and when exposed to C. atlanticus.
B
S. rosetta tended to form colonies when exposed to L. monocytogenes, but not when exposed to C. atlanticus.
C
S. rosetta tended to form colonies when exposed to C. atlanticus, but not when exposed to L. monocytogenes.
D