如图是绿色植物叶肉细胞的生理活动示意图，其中表示错误的是（  ）

下列人体器官中，既能产生生殖细胞，又能分泌性激素的一组是（  ）

对于0和1之间的任一个数a，用计算器求出a²﹣1的结果b．再用计算器求出b²﹣1的结果c…随着运算次数的增加，你发现了什么？

Dear Grandma and Grandpa,

    I miss you so much. Thank you for the new bike! I'm so excited! How did you know 1 is my favorite color?

    When I first 2 the box under the Christmas tree, I didn't know what it was. I thought it was 3 small to hold a bike. Then when I opened it, I saw that the bike was in small pieces. That's 4 the box was small!

    Dad and I put them 5 the next day. It was a lot of fun. 6 we finished, I got on the blue bike and 7 around the town. My old bike was too small for me. This one is just 8. It looks great, too! All 9 friends want one like this now. Dad said that I could take my 10 when we go to visit you in the spring. I can't wait.

Yours,

David

多项式y²+4加上一个单项式后，使它能成为一个二项整式的完全平方，则满足条件的单项式有（    ）