Answer:
I can fly but I have no wings. I can cry but I have no eyes. Wherever I go darkness follows me.
I hide in a dark tunnel awaiting my time. I can only be released by pulling back. Once released I may do unstoppable damage.
The last woman on Earth received a phone call. Who was the caller?
Everyone in the world needs me. They generously give me but never take me. What am I?
Crooked as a rainbow and slick as a plate ten thousand horses can't pull me straight.
Before I grow I'm small. When I'm old I grow tall. When I die I give a mighty fall.