Ch of these layers inside earth is the hottest? a. crust b. outer core c. lower mantle d. asthenospherewhich of these layers inside earth is the hottest?
a. crust
b. outer core
c. lower mantle
d. asthenosphere

I'm pretty sure the answer is B. Outer Core, since the inner core is usually the hottest, the outer core should be the second.

Hey there! 1. Asthenosphere. 2.Lower Mantle.  The asthenosphere the upper layer of the earth's mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur. The lower mantle A large fraction of Earth's interior, from a depth of about 650 km (400 miles) down to 2,900 km (1,800 miles), consists of the lower mantle, which is composed chiefly of magnesium- and iron-bearing silicates, including the high-pressure equivalents of olivine and pyroxene.

Hope this helps! :)

They both determine the exact age of rocks.