<span>The mantle is more dense, so it can not B.
Not even A , because the crust sure does contain naturally occurring radioactive material. Heat is also not efficiently transferred to the surface--most ground is cool,
so correct option is none is above that is D
hope it helps</span>
Answer:
7
Explanation:
pH ranges from 0 to 14, with 7 being neutral. pHs less than 7 are acidic while pHs greater than 7 are alkaline(basic)