给出下列命题: ①若命题p:” x >1” 是真命题,则命题q:” x ≥1”是真命题; ②函数y=2 — x ( x >0)的反函数是y=-log x ( x >0); ③如果一个简单多面体的所有面都是四边形,那么F=V-2 (其中F为面数,V为顶点数); ④“ a ≠1或b≠5”充分不必要条件是“ a +b≠6”,其中所有真命题的序号是_______.
【简答题】Early people had very little effect on the environment. They lived in caves in very small “clan” groups. They collected or killed only enough for the clan’s survival. Early clans were nomadic, which m...