6. Mary likes art ________ she doesn’t like music.
5. Maria likes to ________ a little longer on Sunday morning.
4. I don’t like science ________ it is too difficult.
3. ________ is the third day of the week.
2. My favorite ________ is hamburgers.
1. There are ________ days in a week.
31.Ⅰ.(6分)果蝇的卵原细胞在减数分裂形成卵细胞过程中常常发生染色体不分开的现象,因此常出现性染色体异常的果蝇,并产生不同的表型,如下表4所示:
受精卵中异常的性染色体组成方式
表现型
XXX
在胚胎期致死,不能发育为成虫
YO(体细胞中只有一条Y染色体,没有X染色体)
在胚胎期致死,不能发育为成虫
XXY
|