What is the Force Structure breakdown for the US Marine Corps' ground forces?

Someone asked the following question:

What is the Force Structure breakdown for the USMC?

How are troops and weapons broken down into organized units in the US Marine Corps? i.e. squads, platoons, armies… Also, what rank officer would usually be in charge of these units?

Administratively,
3 Active Marine Air Wings.
3 Active Marine Divisions.Parenthesis indicates who is supposed to command such a unit on paper, but in reality they are often one or in the case of squads and fireteams, two, ranks below that. For specialized heavy weapons units, one rank above what I list is sometimes the norm (Weapons platoons are commanded by 1st Lieutenants, for example).

Divisions (2 star general) are composed of regiments.
Regiments (Colonel) are composed of battalions.
Battalions (Lt. Colonel) are composed of companies.
Companies (Captain) are composed of platoons.
Platoons (2nd Lieutenant) are composed of squads.
Squads (Sergeant) are composed of fire teams.
Fire teams (Corporal) are composed of Marines.

The generalization for how many of each form one higher unit is called the “Rule of Three” and can be approximated with the statement that “three line and one specialized form one higher”. Three line companies and one weapons company form a battalion, for example, and three Marines with one fire team leader form a fire team. The three fire teams that form a squad may have a machine gun team attached when deployed. And so on. There are caveats at every level though, so that generalization is very rough and should be considered a generalization and not an exact rule.When deployed, a provisional Marine Air-Ground Task Force (MAGTF) is formed.

Most commonly, this is done by taking a battalion as the Ground Combat Element, augmenting it with perhaps a tank platoon, adding an Air Combat Element, a Command Element, a Logistics Element, training together for 6-18 months, and then deploying under the command of a Colonel as part of an Amphibious Ready Group commanded by a USN Captain and consisting of 2 or 3 amphibious assault ships of some variety and many more supporting ships.

For Iraq and Afghanistan rotations, the MAGTF is often built around a regiment instead of a battalion, has no ships (obviously), and may not have as much of an Air Combat Element. “Regimental Combat Team” is the term used here, very roughly equivalent to what the US Army calls a “Brigade Combat Team”.