Cars and bike yesyesyesyesyeyseyeyeyeyey
I believe it would be D. Electromagnet. It's been a while since I've done this stuff, tho. Hope this helps!!!! :)
Light does not travel at a constant speed in a vacuum, compared to in air, because the light is being absorbed by atoms and molecules in the air. But light does travel at a constant speed in a vacuum.
So I agree with A
All that talk about moving forward is irrelevant (I think)
The answer to the question is radium (Ra)
Lord dragon you are wrong.
The answer is A: Incandescent light bulbs are almost 100 percent efficient. Because b-d do not make any sense.