What is the substance called when it reaches earth's surface and is made up of molten rock, gases, and minerals? a. rhyolite b. magma c. gabbro d. lava  

D. Lava, Magma is lava while its still in the volcano rather than the surface and the other two options are minerals!

D is your right answer I hope this helps

Its in the national history museum and you can't se the original because its locked away in a vault 

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.