Read the text carefully and answer the question!

    An ant nimbly running in search of food came across a chrysalis that was close its time to change. The chrysalis moved and this attracted the attention of the ant who for the first time realized that it was a living thing "Poor, pitiable animal!", cried the ant disdainfully "what a sad fate is yours! While I can run with my pleasure. you lie imprisoned here in your shell". The chrysalis heard all this, but did not try to make any reply. 

    After a few days, when the ant passed that way again, nothing but the shell remained. Wondering what had happened to its content, he felt himself suddenly shaded and fanned by the gorgeous wings of a beautiful butterfly. "Behold in me," said the butterfly, "your much pitied friend!" So the butterfly rose in the air and lost in the summer breeze. 

The text generally tells us about ____