如图是动植物进化历程示意图。据图回答：

 小明利用天平和量杯测量某种液体的密度，得到的数据如下表，他根据实验数据绘出的图象如图所示．量杯的质量与液体的密度分别是（　　）

在下列命题中，正确命题的个数为（　　）
①两个复数不能比较大小；
②$z_1,z_2,z_3\in C$，若${\left(z_1-z_2\right)}^2+{\left(z_2-z_3\right)}^2=0$，则z₁=z₃；
③若(x²-1)+(x²+3x+2)i是纯虚数，则实数$x=\pm 1$；
④z是虚数的一个充要条件是$z+\stackrel{-}{z}\in R$；
⑤若a,b是两个相等的实数，则(a+b)+(a+b)i是纯虚数；
⑥$z\in R$的一个充要条件是$z=\stackrel{-}{z}$．

根据短文理解选择最佳答案。

    Michael Jordan is the most famous basketball player in the world. He was born in Brooklyn, New York. He didn't like to talk to other people about himself. He was also very short. He didn't play very well when he joined the basketball team in his high school at first. But the next year things changed greatly for him as he grew much taller.

    Michael Jordan became famous when he joined the university basketball team in North Carolina. Michael used his speed and strength (力量) to reach the basket again. He played so well that people called him “Air Jordan”.

    After college, Michael became a basketball team member in the Chicago Bulls. The NBA was very surprised at this high-flying player. He was named “Rookie” (新秀) of the year in 1985 and “Most Valuable (价值的) Player” in 1987. He once set a record (创纪录) by getting 63 points in one game.