Answer:
There is someone, and there is always another, for without the other, there wouldn't be one
A mile from end to end, yet as close to as a friend. A precious commodity, freely given. Seen on the dead and on the living. Found on the rich, poor, short and tall, but shared among children most of all.
What is weightless but it needs two person to hold it?
I run through hills. I veer around mountains. I leap over rivers. And crawl through the forests. Step out your door to find me.
What is given but kept by the giver?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.