Which layer lise directly above the inner core

Earth's outer core is a fluid layer about 2,400 km (1,500 mi) thick and composed of mostly iron and nickel that lies above Earth's solid inner core and below its mantle. Its outer boundary lies 2,890 km (1,800 mi) beneath Earth's surface.

which elements do geologists measure to determine the age of an organism’s remains? check all that apply.

carbon-14

nitrogen

carbon-12