玉米条斑叶的遗传是属于母性遗传,而引起条斑性状表现的胞质基因的性质又受有关核基因的控制。
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We know from the text that Pete________
[A]was trained to stay at station
[ B ] often plays with food before he eats
[ C ] likes to eat fish without fins
[ D] was smart in teaching the bird a lesson
I haven't seen you since you came back from holiday. ________a nice time?
[A]Do you have
[B]Did you have
[C] Have you had
[D]Had you had
一般单基因控制的植物雄性不育属于______不育。它败育过程发生较______,且败育得十分彻底,用常规方法得不到_
It's no use asking the children to keep quiet. They can't help _________noise.
[ A]make
[B]to make
[C]making
[D] made