Answer:
I am wood that is neither hard straight or crooked
I begin your sentences.
I start with an E end with an E and have a letter in me.
I am taken from a mine and shut in a wooden case from which I am never released. Yet I am used by almost everybody. What am I?
I have a brother. However much we run we do not reach each other.
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.
What am I?
Animal
Difficult
Easy
Food
Funny
Kids
Logic