Can someone Explain the the ending of the last mimzy to me.?!

Can someone Explain the the ending of the last mimzy to me.?

I was watching the last mimzy waiting for the explain it all end. But when the ending came my nieces started asking me all this questions during the explanation. So What happened? What did the rabbit take back? a Soul? What did he want with it? why did the kids start flying and who was that teacher? lol Thanks

The kids & the teacher were part of the happy, peaceful future & has acquired the power to fly as humans continued to evolve into a harmonious society. What the Mimzy took back was a tear, containing the optimism & trust of childhood - before the kids were polluted by fear, consumerism, selfishness & all the other maladies of our current society. This allowed the scientists in the future to clean the environment & help everyone realize they needed to work together to get along & take care of the planet. The two characters who walked naked into the light were representative of a new Adam & Eve. It was a bit heavy-handed in pointing out the message, but still an enjoyable film.