Question

8 what is the only entirely liquid layer of the earth?
a the upper mantle
b the outer core
c the inner core
d the lower mantle

Explanation:

The upper and lower mantle are solid (plastic-like solid) layers, the inner core is a solid metallic sphere, while the outer core is composed of liquid iron and nickel, making it Earth's only entirely liquid layer.

Answer:

B. The outer core