题目

某种植物的株高由多对基因控制，显性基因越多就越高。现将最高和最矮的两个极端类型作为亲本杂交，F2表现型的预期分布与下列哪一曲线最接近（    ） 答案：A判断下列句子是否与短文意思相符，符合的用T表示，不符合的用F表示 　　Tim is eight. Sam is eight, too. They are friends. One day on their way to school. They see a bear. Tim climbs a tree. Sam can't climb a tree. He is on the ground. The bear smells Sam. It doesn't eat Sam. It goes away, Tim climbs down the tree. He asks Sam, " What does the bear say?" 1. Tim and Sam are both eight years old.______ 2. They see a bear in the school. _____ 3. Tim and Sam climb a tree. ______ 4. The bear eats Sam. ______