机体在神经系统和体液的共同调节下可以维持内环境的稳定。下图是甲状腺激素分泌调控模式图，主要包括①至⑤五个过程，其中TRH及TSH分别表示促甲状腺激素释放激素和促甲状腺激素。请回答下列问题：
促甲状腺激素能与甲状腺细胞膜上的受体发生特异性结合，受体的化学本质是（）。胰岛细胞膜上没有该受体，这是由于（）的结果。
参考答案：糖蛋白；基因的选择性表达
| 完形填空。 | ||||
| Everyone, rich or poor, can have happiness (幸福、快乐). You don't need to think too much about those who are 1 . Why? Because those who have big houses may often feel 2 and those who drive their cars to work may want to 3 on country roads in their free time. In fact, happiness is always around you. When you are 4 , -your friends will come to help and this will surely 5 you happy; when you study hard at your lessons, you will get good 6 and of course you will feel happy about it. When you are not 7 well, your parents will take good care of your 8 and you will be happy when you are well again. All these are your happiness. When you are poor, you also can say you are happy because you may have something else that money can't buy. When you 9 problems, say loudly that you are happy as you have more chances to challenge (挑战) yourself so that you can 10 in what you do and this may bring you happiness. Take every chance you get and you can be a happy and lucky person. | ||||
|
