Use the drop-down menus to name the following structures. a skeletal model with three flat line segments; the center segment is a triple bond. a skeletal model with line segments going down, flat in a double bond, up and down. a skeletal model with line segments going down, up, flat in a double bond, the up, down, up, down, up, and down. a skeletal model with line segments that go down, up, down, flat, and flat again in a triple bond.