Short answers, pulled from the story.
The LGM-30 Minuteman is an American land-based intercontinental ballistic missile and the only land-based ICBM currently in the U.S. arsenal. It forms the land leg of the nuclear triad alongside Trident II submarine-launched missiles and long-range bombers.
Minuteman I first test-fired on the 1st of February 1961 at Cape Canaveral and entered Strategic Air Command's arsenal in 1962.
The missile is named for the colonial minutemen of the American Revolutionary War, who were prized for being ready to fight on short notice. That name reflects Minuteman's rapid launch capability.
400 Minuteman III missiles are deployed in silos around F.E. Warren Air Force Base in Wyoming, Minot Air Force Base in North Dakota, and Malmstrom Air Force Base in Montana.
Since 2016, each Minuteman III has carried a single warhead, either a 335-kiloton W78 or a 300-kiloton W87. It previously carried up to three W62 warheads under a MIRV configuration.
The LGM-35 Sentinel, built by Northrop Grumman, is set to progressively replace the Minuteman III starting in 2030. Northrop won the development competition on the 14th of December 2019 after Boeing dropped out of the bidding.