A:A,B是体液调节和免疫调节,C,D可以是体温和渗透压
B:内环境的稳态只要有三种调节方式即可,不需要其他器官或系统参与
C:酸碱度的相对稳定主要依靠血液中的缓冲物质,与其他器官或系统也有关
D:内环境的稳态和生态系统的平衡一样,其维持自身稳定的能力是有限的
同学们“测量并探究影响滑轮组机械效率高低的因素”,使用了如图所示的装置,下列说法正确的是(每个钩码重相同)( )
Mr. Jackson is a teacher of science in a middle school. His students like his classes because his classes are very interesting. They can learn a lot in his class. The students can make(制作)many things. His little son Val also likes making things. He makes lots of machines(机器), such as a machine like a man. It can do the job that is dangerous(危险的)for people to do. He says, “I want to be a scientist.”根据短文内容,选择正确答案。