Question

select the best detail to show that its too hot to live below the earths crust.
our planet is made up of many layers of rock. the top layers of solid rock are called the crust. deep beneath the crust, it is so hot that some rock melts. the melted, or molten, rock is called magma.
volcanoes are formed by cracks or holes that poke through the earths crust. magma pushes its way up through the cracks. this is called a volcanic eruption. when magma pours forth on the surface it is called lava. . . .as lava cools, it hardens to form rock.
from seymour simon, volcanoes. copyright 2006 by harpercollins

Explanation:

To show it's too hot below the crust, we look for details about heat effects. The text says "Deep beneath the crust, it is so hot that some rock melts" (forming magma). This directly shows the extreme heat (melting rock) making it unlivable. Other details (like volcano formation, lava cooling) relate to magma movement/aftermath, not the heat's unlivability. So the best detail is "Deep beneath the crust, it is so hot that some rock melts."

Answer:

Deep beneath the crust, it is so hot that some rock melts.