Answer:
I am an activity dogs are very good at when a ball is thrown.
I am the black child of a white father a wingless bird flying even to the clouds of heaven. I give birth to tears of mourning in pupils that meet me even though there is no cause for grief and at once on my birth I am dissolved into air.
In my life I must bare my bloodline I must share.
I help engines spin and pants stay up
When I live I cry if you don't kill me I'll die.
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.