Civil service exam! Teacher Gu Fei, who painted the picture, said it was A, but someone said it was B on the Internet. Diatom is the most important component of Antarctic phytoplankton.
Choose a, no problem. The previous arguments are all aimed at explaining the point behind "so", so the sentence "Some people think krill is more suitable as a symbol of Antarctic creatures than penguins" is the point to be expressed, and the previous arguments are all evidence to support the point.
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