A:具有发达的根、茎、叶
B:用种子繁殖后代
C:种类繁多
D:用孢子繁殖后代
我国的人口地理分界线是( )
右图是《游子身上衣》新闻漫画,游子身披五星红旗,喜笑颜开,欢欣鼓舞地扑向祖国母亲怀抱。该漫画反映的历史事件是( )
Hello,I'm Fangfang. I'm 10. My favourite letter is A. Yellow is my favourite colour. This is Sam. The ABC song is his favourite song. His favourite colour is blue. D is his favourite letter.
在下列四个函数中,满足性质:“对于区间(1,2)上的任意x1,x2(x1≠x2).f(x1)-f(x2)<x1-x2恒成立”的只有( )