The spongy material in the center of a bone is called the bone marrow.

True or False

it is true

Explanation:

in the bone there are 3 layers the outer layer is made of thin membrane

the middle layer is smooth and hard  

the inner layer looks like a sponge is very hard and strong and it protects the center of the bone marrow, which looks like a thick jelly

i think the miocene epoch spans the time from 23 million to 12 million years ago.

true, i don't really know what you're asking but from the info you provided im guessing the answer is true.