TOEFL Listening: TPO-TOEFL阅读TPO - T7325LN59RZD03_IN$

Paragraph 6 supports which of the following statements about a phytoplankton species that cannot produce thiamine? A. It can be followed in a seasonal succession only by another phytoplankton species that cannot produce thiamine. B. It can never become the dominant species in a seasonal succession. C. It can be preceded in a seasonal succession only by a phytoplankton species that produces thiamine. D. It is able to produce B vitamins other than thiamine.