胚囊,普通具有8个遗传上相同的单倍体核.Embryo has most commonly eitht genetically identical haploid nuclei.植入之后不久,胚囊的壁, 即滋养细胞含有两层细胞.Shortly after implantation the blastocyst wall, the trophoblast, consists of two layers of cells.存在于胚囊和胎座中的...
Only by offering credible protection could the Americans undermine the militias.只有提供了可靠的保护措施,美军才能破坏形形色色的民兵组织.Local militias play an important role in Italian armies.本土民兵在意大利军队中扮演了重要角色.The neighborhood was a battleground ...