单项选择题
A.胚根 B.胚芽 C.胚乳 D.胚
A.1/2 B.1/3 C.3/4 D.2/3
A.20%-22% B.18%-20% C.7%-8% D.9%-12%
A.58%-65% B.50%-52% C.65%-75% D.70%-80%
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