Thermal energy flows from warmer to cooler material. In Earth's interior, solid particles of rock are in contact with one another, so the process of transfers thermal energy from the interior to the surface.

Heat flows in solids by conduction, which occurs when two objects in contact with each other transfer heat between them. That happens because the molecules hit each other, and the faster moving molecules in the hot object spread that energy into the cooler object.

Explanation:

the correct option is c.

isotopes refers to different forms of the same element with the same atomic number but different mass number as a result of difference in their neutron numbers. isotopes have different relative atomic mass but share the same chemical properties.

it is the most commonly accepted one