下列关于地球上生命起源的推断，完全没有科学依据的是（　　）

在平面直角坐标系xOy中，已知椭圆E： $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$ （a＞b＞0），圆O：x²+y²=r²（0＜r＜b），若圆O的一条切线l：y=kx+m与椭圆E相交于A，B两点．

（Ⅰ）当k=﹣ $\frac{1}{2}$ ，r=1时，若点A，B都在坐标轴的正半轴上，求椭圆E的方程；

（Ⅱ）若以AB为直径的圆经过坐标原点O，探究a，b，r之间的等量关系，并说明理由．

阅读下面短文，掌握其大意，从每小题所给的A、B、C三个选项中选出最佳选项。

    One day Eric was traveling on horseback. At noon, he tied his horse to a 1. Afew minutes later, Paul came along and tied his horse to the same tree.

   “My horse is wild,” said Eric. “Please tie your horse to another tree, 2 my horse will kill yours.”

   “No way!” Paul said, “I shall tie my horse as I like!”He tied up his horse and had his 3 nearby. After a moment they heard a terrible noise. The two horses were 4. They ran up to them, but it was too 5. Paul's horse was killed. “See what your horse has done! You'll have to 6 it,”shouted Paul. And he brought Eric before Mr. Know.

    Mr. Know asked Eric some questions. But Eric said 7. At last Mr. Know said, “This man cannot speak.”

  “He can!” Paul said 8. “He talked to me when I met him.”

  “Are you 9?”asked Mr. Know. “What did he say?”

  “He told me not to tie my horse to the same tree because his horse was wild and would kill my horse.”

  “Oh,” said Mr. Know. “So he 10 you. Then can you expect to get money from him?” Paul had to leave silently.