How did the streetcars affect the development of american cities and towns

  It made it possible to travel many miles in a day. Before the automobile, people in cities had to take streetcars (horse drawn, later electric) to get anywhere further than they could walk. People who lived out of town had to get to work on interurban railways, so suburbs were not really that popular. People who lived on farms or in small villages in the country would come into town maybe once a month in a horse-drawn cart to do their shopping, but a horse couldn't do more than 15 or 20 miles there and back. It wasn't much faster than walking, and just in general way more convenient 

The one that most represents the earths mantle would be the skin since the mantle is the upper part of the earths depths which is just like the skin of an apple.