What is the medium that sound waves travel through?

You notice a very one-dimensional-thinking snail crawling along one rail of a railroad track. naturally, you remove it to a safer place. but before you do, you observe it as it moves from position xi = -92.9 cm to position xf = -64.9 cm along the rail, as measured from a point where one rail abuts the next. what is the snail\'s displacement δx in centimeters?

Could someone . i have tried to solve myself but my calculation is off

Which transition by an electron will release the greatest amount of energy? oa ob oc od