人体细胞共有23对染色体。其中22对男女都一样，叫常染 色体。另1对为性染色体，男性为xY，女性为xX。在男子射出 的精液中，成熟的、经过减数分裂的精子有二种：一种精子含有X性染色体；另一种精于含有Y性染色体。一般来说，两种精于 的数目大致相等。卵子的性染色体只有一种，即x性染色体。 怀孕男孩还是女孩，主要根据受精时哪一种精子(X或Y)和 卵子(X)结合来决定。如果妇女在排卵期排出的卵子与带有x性 染色体的精于相结合，形成含有xx型染色体的受精卵，就发育成 女孩。如果该卵子与带有Y性染色体的精于结合，形成含有xY 性染色体的受精卵，胚胎就发育成男孩.
求未知数 X Y
你能解出这道方程吗？
X
论坛ID， 像自在的风
QQ呢称 维他命c
性别， 女
年龄或出生年月， 1982. 7
籍贯 广东 韶关
所在地（深圳各区） 龙岗
身高，体重 160cm 46 kg
性格 温和型
爱好 DIY
从事行业或工种， 小学英语教师
可公开的联系方式 qq 471707921
[email protected]
luoye0608 @163.com
y
爱好 我最喜欢看你打篮球的样子, cool
性别 male
年龄或出生年月 25 以上
籍贯 不限
所在地（深圳各区） 不限
身高 173 以上
体重 不要太胖就行
性格 有主见， 有责任感，有上进心
从事行业或工种 不限
附： My Ideal Mate
I haven’t fallen in love with somebody ,although I’m 24 now .Well , I asked myself a thousand times , Who will be my companion be in the future ? How will my companion be ? There’s a dream on that day .
He is walking towards me ,and the sun smiling on his face . He is in my eyes now . He is 180 cm tall ,with straight strong limbs , not too large , wearing a white shirt and black trousers . He is comely and handsome . He has a very good countenance , but seems to be something very manly in his face . Yet he has all the sweetness and softness in his countenance , too , especially his smiles . When he gets closer , I can see him more clearly . His hair is short and black ; and his forehead is high and large . He has great vivacity and sparkle in his eyes . His nose is high , a very mouth with thin lips ,and his teeth are well set and as white as ivory .
I’m really enjoyable at that moment . He holds me in his arms , turning around and around . I laugh and laugh , with all the happiness around us . Then he lays on the green grass , and I lay beside him , resting my head on his shoulder. He gently strokes my hair . At that time , I can feel his breath and hearing his heart . We are lying there for a long time looking up at the blue sky and white clouds .
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楼主: 深圳有缘居
发表于 2006-2-16 14:35
