The answer is ultraviolet rays
Bulbs c and b would still be screwed in if they were in to begin with and bulbs A, D, and E. would be unscrewed
The answer is definitely C.) their molecules move at the same average speed
The ratio of the distance moved by the point at which the effort is applied in a simple machine to the distance moved by the point at which the load is applied, in the same time. In the case of an ideal (frictionless and weightless) machine, velocity ratio = mechanical advantage. Velocity ratio is sometimes called distance ratio.