下列哪一项不是威胁生物多样性的原因( )
A:森林面积锐减
B:环境污染
C:外来物种的入侵
D:生物进化
Hello,friends! My name is Jack.I am a Chinese boy.My favourite food is chicken.I like beef noodles,too.I don't like fish but egg is OK.Potatoes are my favourite vegetable.My favourite fruit is bananas.They are so sweet.
方程x2+4x﹣1=0的根可视为函数y=x+4的图象与函数y=1x的图象交点的横坐标,那么用此方法可推断出:当m取任意正实数时,方程x3+mx﹣1=0的实根x0一定在( )范围内.