某种雌雄异株的植物有宽叶和狭叶两种类型，宽叶由显性基因B控制，狭叶由隐性基因b控制，B和b均位于X染色体上。基因b使雄配子致死，请完成下列问题
(1)若后代全为宽叶雄性个体，则其亲本基因型为_______。
(2)若后代全为宽叶，且雌雄植株各半，则亲本基因型为________。
(3)若后代全为雄株，宽叶和狭叶个体各半时则亲本基因型为__________。
(4)若后代性别比为1：1，宽叶个体占3/4，则其亲本基因型为____________。
(1)XBXB和XbY
(2)XBXB和XBY
(3)XBXb和XbY
(4)XBXb和XBY
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| Swimming is very popular in summer. People like swimming in summer because water makes them 1 cool. If you like swimming but swim in a 2_ place, it may not safe. These years, more than ten people 3 while they were enjoying themselves in the water and _4 _ of them were students. But some people are _5 not careful in swimming.They often think they swim so 6 that nothing can happen to them in water. Summer is here again. If you go swimming in summer, don't forget _7 better swimmers have died in water.They died because they were not careful,not because they 8 swim. So don't get into water when you are alone 9 there is a "No swimming" sign, don't get into water, 10 . If you remember these, swimming will be safer. | ||||
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