When moving horizontally, what type of energy action occurs due to opposition from friction?

When an object moves horizontally and encounters friction, the work done by friction converts some of the object's kinetic energy into thermal energy. Friction opposes the motion, resulting in energy loss in the form of heat. This phenomenon occurs because the irregularities at the surfaces of the two objects in contact create resistance to motion, which generates heat through the process of friction.

As a result, when kinetic energy (the energy of motion) is present, friction acts to reduce this energy while simultaneously increasing the thermal energy of the surfaces in contact due to the heat generated. Thus, thermal energy becomes the predominant form of energy affected by the frictional forces, making it the correct answer in this scenario.