【简答题】阅读理解。 Are You Still Looking for Your Son? Mrs. White has a son. His name is Sam White. The young man begins to work in a post office in a city this Autumn. He asks his mother to visit the city. The ol...
【简答题】阅读理解。 Mrs White has a son. His name is Sam White. The young man begins to work in a post office in a city this autumn. He asks his mother to visit (参观) the city. The old woman is happy and catches a t...
【判断题】由于需求放大效应的影响,上游供应商往往维持比下游供应商更高的库存水平。
【简答题】音程bfa-sol属于( )和声大调和( )和声小调
【单选题】下列关于防火墙叙述,错误的说法是____。
【多选题】阿里巴巴国际站的关键词可以通过哪些途径获得?
【单选题】在非洲的某些疟疾发病区,镰形细胞贫血杂合子的相对生育率反而较正常人高。若以野生型纯合子的生育率为1,下列说法不正确的是?
A.
镰形细胞贫血杂合子的选择系数为正值,表示自然选择对该基因型起正向选择作用。
B.
镰形细胞贫血杂合子的遗传负荷为负值,意味着镰形细胞贫血杂合子生存能力强。
C.
镰形细胞贫血杂合子生存能力强是由于杂合镰形细胞性状对恶性疟原虫的抵抗力较强。
D.
在美洲的黑人人群中没有杂合子的相对生育率较正常人高的现象,说明基因或基因型的适合度随环境改变而改变。
【单选题】This is my son. ______ name is Yang Yang. [ ]
【简答题】阅读理解。 Mrs. White has a son. His name is Sam White. The young man works in a post office in a city. He asks his mother to visit the city, and the old woman is happy and catches (赶上) a train. Soon she g...