In the eastern region of the former soviet union, a railroad was built on the tundra. the surface soil was dug up and tracks were laid down over the ground beneath. within a year the ground shifted and buckled and the tracks could not be used. using your understanding of the tundra, explain what probably happened.

You have trained year for a marathon. in your first attempt to run a marathon, you decide that you want to complete this 26-mile race in 4-5 hours. a. what is the length of a marathon in kilometers (1mile= 1.6 kilometers). b. what would your average speed have to be to complete the race 4.5 hours? give your answer in kilometers per hour.