Electricity is one of two aspects of which fundamental force?

The graph describes the motion of an object. the object moves with from a to b. it from b to c. it moves with from c to d.

Imagine you are standing in the antarctic during the southern hemisphere summer. the sky is clear and blue. there are no clouds in the sky. your shadow is cast on the icy ground. what is the color of the shadow?

How is sound energy produced a. vibrating objects b. objects being heated c. temperature differences d. stationary objects