Does light always travel at the same speed?

Light's speed only depends on the substance (medium) it's moving through.

It travels at a constant speed as long as it stays in the same medium.

Light has the fastest speed when it's in vacuum, and nothing moves faster than that speed.

answer: the correct answer is   air pressure at the top of mount everest is higher than at the bottom of the grand canyon.

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explanation:

first thing first of the answer is with technology. second thing second thing is that the big bang theory did not happened u see they say it did but what they dont realize is that like dinasures are still a round they might deny it but they and look at these 12 foot human skelteons they find lets see didnt the bible say something about giants. hope this peace.