If yiu were stranded on a desert island and you wanted to get somewhere from the place,what would you do?you would carry on yourself.in early days,human muscles were the only means of transporting anything.man was.his own beast of burden.
Later,man tamed certain animals and taught them to carry riders or other goods.the ox,the donkey,the water buffalow,the horse and the camel were used by early man in various parts of the body world for transportation .but man wanted to find some way by which animals could transport more goods.so,he developed crude sledges and drags to hitch to his animals.flatbottmed sledges and sleds with runners were fine on snow but not much good on regular ground.so man developed the rolling drag.This consisted of sections of logs used as roller under a drag or platform was pulled,the logs under it rolled.this made the work easier than pulling the platform along the bare ground.
As the platform moved along,it passed completely over the logs at the back. Then they were picked up and put under the front end of the platform.After a long time,someone thought of cutting a slice from the end of a log and making a hole in its centre.this was a wheel,one of man's greatest discoveries.
When two wheels were joined by an axel and the axle was fastened to aplatform,man made the crude cart.in the course of thousands of years,man improved the wheel.by building wheels with separate hubs,spokes and rims,he made them lighter and more efficient.he made rims of iron so that the wheels would last longer.at last,he learned to use rubber tyres.