Asthenosphere: A. Is warm enough to flow slowly B. subducts when it collides with continental lithosphere. C. is the lower layer of both continental and oceanic lithosphere. D. is the uppermost layer of Earth's core. is warm enough to flow slowly. Asthenosphere is part of the mantle, not the core. It supports the lithosphere, rather than being part of it or colliding with or subducting under it.