How does light travel?
a. light only travels in a vacuum and travels faster when the sound is moving
b. light on only travels in a medium and light travels faster when a sound source is stationary
c. light can travel in a vacuum in the speed varies depending on whether the source is moving or stationary
d. light can travel in the air or a vacuum and the speed is constant weather the light source is stationary or moving

The correct answer is option(D).

Explanation:

Light travels in a straight line as a wave. It does not require any medium or material to travel like sound waves which means it can travel in vacuum.The speed of the light  from the special theory of relativity is a constant value of  .

Hence, the correct answer is option (D).

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.

multiply it by 5 in order for you to understand i cant give an exact answer.