责任产生于社会关系之中的(　　)

相对论的提出推动物理学发展到一个新的高度，依据是(　　)
①相对论从本质上修正了由狭隘经验建立起来的时空观
②相对论深刻地揭示了时间和空间的本质属性
③将牛顿力学概括在相对论力学之中
④将人类对客观规律的认识开始从宏观世界深入到微观世界

设l为直线,$\alpha ,\beta$是两个不同的平面,下列命题中正确的是（   ）

⑴Mom and Dad are the most important people in your life. They have been looking after you since you were born. ⑵你应该一直爱他们。You should also get on well with them. But some children don't know how to do this. Here are some ways to help you. Spend more time with your parents. ⑶Don't spend too much time playing computer games or watching TV. Ask your parents to play with you. ⑷和他们交谈或者散步。 Be kind to your parents. You can make them happy with a smile when you come home. You can send your mother a card on Mother's Day or tell your father a joke on his birthday. ⑸You can also clean your room by yourself. Work hard. If you do your best in your studies, your parents will be proud of you.

R型肺炎双球菌菌体无多糖类的荚膜，是无毒性细菌；S型肺炎双球菌菌体有多糖类的荚膜，是有毒性的细菌，可使人患肺炎或使小鼠患败血症．以下是科学家艾弗里及其同事利用肺炎双球菌探究什么是遗传物质的问题的步骤，请分析后回答下列问题．实验材料，用具；S型细菌、R型细菌、DNA水解酶、培养基、培养皿等．艾弗里等人先做了以下三组实验．

①S型细菌的蛋白质+R型细菌R型菌落；

②S型细菌荚膜中的多糖+R型活细菌R型菌落；

③S型细菌的DNA+R型活细菌R型菌落+S型菌落．

（1）艾弗里等人后来发现上述实验步骤并不严密，于是又做了第四组实验，请按照①②③中表达格式写出第四组实验方法和结果____ 

（2）上述实验可以得出结论是____ ．

（3）该实验最关键的设计思路是____ ．

（4）肺炎双球菌具有的细胞器是____ ；其控制性状的物质是____ ．