Answer:
I am quick when Iām thin. I am slow when Iām fat. Wind is my worst nightmare.
I am black, white, and read all over. What am I?
Goes over all the hills and hollows, Bites hard, but never swallows.
No matter how little or how much you use me, you change me every month.
I can be repeated but rarely in the same way. I can't be changed but can be rewritten. I can be passed down, but should not be forgotten. What am I?
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.