Final answer:
Energy conversion refers to the transformation of energy from one form to another, occurring in natural processes and technological devices. An iron converts electrical energy into thermal energy, while solar cells convert sunlight into electrical energy.
Step-by-step explanation:
Energy conversion is B) the transformation of energy from one form to another. This happens constantly in the world around us and within the technology we use. For example, in a household iron, electrical energy is converted into thermal energy to remove wrinkles from clothes. Similarly, in a solar cell, sunlight is converted into electrical energy, which can further be used to power an electric motor, converting it into mechanical energy. A familiar biological example would be the conversion of the chemical energy in food into thermal energy through metabolism.
A specific device known as a heat engine takes thermal energy and transforms it into mechanical energy, which can often then be used to generate electric power. In the human body, various forms of energy are transferred, such as internal energy when basking in sunlight, heat transfer when eating food, and doing work when riding an elevator to a higher floor.