|Question 14Verbal

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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 Salpingoeca rosetta, the oldest living relative of animals, sometimes forms colonies of cells. Alegado and colleagues reviewed data from many studies of how S. rosetta responds when exposed to another type of single-celled organism, bacteria, including Eric W. Triplett's work with Dyadobacter fermentans bacteria and Jung-Hoon Yoon's work with Algoriphagus marincola bacteria. Alegado and colleagues concluded that both D. fermentans and A. marincola might have played a role in the development of multicellular organisms.
Which finding, if true, would most directly support Alegado and colleagues' conclusion?
S. rosetta tended to form colonies when exposed to A. marincola but not when exposed to D. fermentans.
A
Although several studies involving other bacteria species found that S. rosetta tended to form colonies after bacteria exposure, only the studies using D. fermentans and A. marincola tested whether the amount of bacteria exposure affected the rate of colony formation.
B
S. rosetta tended to form colonies when exposed to D. fermentans but not when exposed to A. marincola.
C
S. rosetta tended to form colonies when exposed to D. fermentans and when exposed to A. marincola.
D