to defend and protect the state of Maryland.

No. There is only an Army National Guard and an Air National Guard.

There is the Army National Guard and the Air National Guard.

No the National Guard does not have submarines. The National Guard is primarily a ground fighting organization. The Air National Guard does provide for air support within the US.

There are actually two National Guards, but when people say the National Guard they are probably (but not necessarily) talking about the Army National Guard.

The other National Guard is the Air National Guard which is to the Air Force what the Army National Guard is to the Army.