Question

what is the earths outermost solid layer? upper mantle lithosphere inner core

Explanation:

The lithosphere is the rigid, outermost shell of the Earth. It includes the brittle upper portion of the mantle and the crust, which is the outermost solid layer of a terrestrial planet or natural satellite. The upper mantle is not entirely solid (has some semi - molten regions in the asthenosphere which is part of the upper mantle). The inner core is the innermost layer of the Earth.

Answer:

lithosphere