Final answer:
The Earth's mantle is mainly composed of silicate rocks and is neither completely hard nor soft. It is in a semi-solid state due to high temperature and pressure, which allows movement of tectonic plates.
Step-by-step explanation:
The Earth's mantle is made up of semi-solid rock which is neither totally hard nor soft. This layer, found beneath the crust and above the core, has a consistency somewhat similar to hot asphalt as it is in a state of semi-fluid and semi-solid. The mantle is primarily composed of silicate rocks. High pressure and temperature conditions within the mantle enable this hot semi-solid state, which allows for tectonic plate movement.
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