Final answer:
A loop or sheet of glowing gas ejected from an active region on the solar surface and influenced by the Sun's magnetic field refers to solar flares and prominences, which move through the solar corona and are part of the complex activity on the Sun's surface.
Step-by-step explanation:
The loop or sheet of glowing gas ejected from an active region on the solar surface, as described in the question, refers to a phenomenon associated with solar activities such as flares and prominences. These structures are indeed influenced by the Sun's magnetic field and can be observed moving through the inner parts of the solar corona, often heating up as they do so.
Such observations assist scientists in understanding the various heating mechanisms of the solar atmosphere, including the chromosphere and the corona, as well as the generation and acceleration of the solar wind, which emerges mainly from coronal holes where magnetic field lines stretch into space.