Long bones contain marrow.
http://en.wikipedia.org/wiki/Bone_marrow
The axial skeleton is the bones that make up the centre or core of the skeleton to which the appendicular skeleton which bones attach to.
Marrow. Bones contain marrow. Marrow is the very Core of our bones.
microtubules
core
The spine itself is formed by a central core of nerves called the spinal cord, protected by many vertebrae, which are bones, each with a soft 'disc' in between for the purposes of flexibility and reduction of stress on the bones.
The central core has 5 regions which helps to regulate the basic life processes.
The inner core.
Core is defined as "the central or innermost part."
The nucleus.
core
The layers of the Earth go as such: Crust --> Mantle --> Outer Core --> Inner Core
It would be C. central atomic core. Nucleus is always found at the center of the atom. This is not always the case for nucleus in the cells.
A ferrous core.
nucleaus
Nucleus.
Medulla
The central core of an atom is called the nucleus, not the shell.