"And you were unable to save any of them?"
We could have saved them if we'd wished, came the thought.
"Which seems to bring us to the most important question of all," Clyde Ellery said with a wry smile. "Why did you save us?"
There was a hesitation, and then the thought came to them: The animal life on our planet died out because we could not, of course, permit it to feed on us. Yet, as you must know, we needed some form of animal life to maintain the balance of oxygen and carbon dioxide necessary to our lives. You seemed ideal for our purpose, for you could bring with you other animal life and your undeveloped plant life to feed yourselves.
"And you did destroy the ships so that we could not leave?"
Of course.
For several minutes, the men looked silently at each other and considered that which they had received.
"It's hard to accept," Clyde Ellery said to the others, "but I suppose it's not too surprising when you stop to think about it. Even on Earth, the actual boundaries between animals and plants were artificial, as shown by our one-celled animal life which often couldn't be told from a unicell plant. It was just a question of where this evolutionary accident happened."
Not an accident, came the thought swiftly. It was an accident that plants did not become dominant upon your planet. It is logical that we should be highest on the evolutionary scale. We are the only non-destructive form of life there is.