我国奴隶制王朝更替的先后顺序是（    ）

阅读下列材料，回答下列问题：

材料一：科学家将一种矮秆（抗倒伏）但不抗锈病的小麦与另一种高秆（不抗倒伏）但抗锈病的小麦做亲本进行杂交．后代中出现了矮秆抗锈病、矮秆不抗锈病、高秆抗锈病、高秆不抗锈病四种类型，选矮秆抗锈病类型繁殖培育，若干代后，获得了矮秆抗锈病小麦新品种．

材料二：科学家利用航天技术搭载普通椒的种子，返回地面后再进行选育，培育出果实大、口感好、产量高的太空椒．

材料三：新疆的哈密瓜甜度大，有人将其引进到山东来种植，其甜度大大降低．

    Are you looking for some new and exciting places to take your kids to? Try some of these places:

    Visit art museums. They offer a variety of activities to excite your kids'interest. Many offer workshops for making hand-made pieces, traveling exhibits, book signings(签名）by children's favorite writers, and even musical performances and other arts.

    Head to a natural history museum. This is where kids can discover the past from dinosaur models to rock collections and pictures of stars in the sky. Also, ask what kind of workshops and educational programs are prepared for kids and any special events that are coming up.

    Go to a Youtheater. Look for one in your area offering plays for children and family visitors. Pre-show play shops are conducted by area artists and educators where kids can discover the secret about performing arts. PuPPet (木 偶）making and stage make-up are just a couple of the special offerings you might find.

    Try hands-on science. Visit one of the many hands-on science museums around the Country • those science play-lands are great fun for kids and grown-ups alike. They will keep your child mentally and physically active the whole day through while pushing buttons, experimenting, and building. When everyone is tired, enjoy a fun family science show, commonly found in these museums.