A division is a large military unit or formation, usually consisting of between 10,000 and 20,000 soldiers. In most armies, a division is composed of several regiments or brigades; in turn, several divisions typically make up a corps. In most modern militaries, a division tends to be the smallest combined arms unit capable of independent operations; this is due to its self-sustaining role as a unit with a range of combat troops and suitable combat support forces, which can be arranged into various organic combinations.