Giving brainliest Which part of the body connects the bones together and prevents them from rubbing against each other?

Blood
Cartilage
Muscle
Spinal cord

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.