﹣2.5的相反数是 ____
The number of the students in our school is about eight _______._______ of them are boys.
张扬同学在探究电磁铁磁性强弱的实验中，使用两个相同的A、B大铁钉绕制成电磁铁进行实验，如图所示，下列说法错误的是
全球气候变化会引起地理环境的变化。据此完成下列小题。
