18. For the following description, which one is correct?
(A) There are about 4,000 spermatogonia in fetal testes
(B) There are about 400,000 follicles in ovary at the beginning of puberty
(C) sperm maturation is about 100 days
(D) primary oocytes appeared after puberty
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統計: 尚無統計資料
統計: 尚無統計資料