当一对基因中一个是显性基因，一个是隐性基因时，生物表现出的是（　　）

    Today is a nice day! The sun is shining. The birds are singing! Many people are p laying in the park! They are very happy! Look, the three girls are dancing! There are two boys flying the kite! There is a boy under the tree. He is listening to music. Some men are fishing. I love this day!

生物兴趣小组在探究唾液对淀粉的消化设计并完成了如下实验：