Which of the following describes the physical state of the outer core?

The outer core of the Earth is characterized as a liquid state primarily due to the high temperatures and pressures present at that depth. Located beneath the mantle and above the solid inner core, the outer core is composed mainly of molten iron and nickel. The flow of this liquid metal is responsible for generating the Earth's magnetic field through the dynamo effect, where the movement of conductive materials generates electric currents.

The conditions in the outer core—intense heat (which can reach up to about 4,000 to 5,000 degrees Celsius) and significant pressure—prevent the iron from solidifying, hence maintaining it in a liquid form. This liquid state distinguishes it from the solid inner core, which, despite being hotter, is under so much pressure that it remains solid.

The other options—solid, gaseous, and crystalline—do not accurately describe the outer core's state. A solid state would imply a uniform structure, which does not hold true given the temperatures. A gaseous state would require a vastly different environmental condition not found at those depths. Lastly, a crystalline state would indicate an ordered arrangement of atoms, which does not occur in the outer core's molten material. Thus, the liquid nature of the outer core is the defining aspect of