甲、乙、丙三个正方体，边长之比为1：2：3，质量分别为3g、24g、36g，已知它们是同一材料制成的，但有一个是空心的，则空心的正方体是（　　）

    It is Sunday today. Anna goes shopping with her mother. She wants her mother to buy a new coat for her. In Hongxing Shop, she finds a green coat. She tries it on. It's too small. She wants a big one, but the big one is not green. Anna doesn't like other colors.” Let's go to another(另外的)  shop to have a look.”her mother says. Then they go to Jiajiale Shop. The shop is big and they see many kinds of coats in different colors and sizes(尺码). Anna tries on a green one. It looks nice on her. So they take it for forty-five yuan.

如图所示的四幅图中，不正确的是（　　）

蟑螂的生命力很旺盛，它繁衍后代的方法为下一代的数目永远是上一代数目的5倍也就是说，如果蟑螂始祖（第一代）有5只，则下一代（第二代）就有49只，依次类推，推算蟑螂第10代有（  ）.