The layer of Earth that is best characterized as a layer of soft, hot rock is the asthenosphere. The asthenosphere is part of the upper mantle, which is located directly below the Earth's crust. It is a semi-fluid layer made up of hot, partially molten rock. The temperature and pressure in the asthenosphere are such that the rocks are relatively soft and can slowly flow over long periods of time. This movement of the asthenosphere plays a crucial role in tectonic plate motion and the creation of geological features like mountains and oceanic trenches. To determine this layer, one can refer to scientific sources such as geology textbooks, research papers, or online educational websites that explain the structure of the Earth's layers.
