The first machines of the industrial revolution were powered by?

The coal-fired steam engine was soon developed. It became the key technology of the Industrial Revolution. In preindustrial Europe, water power was widely used as a source of energy.

Explanation:

so they can differentiate themselves from others as they saw themselves as the superior race. the star was basically a symbol that meant you are a less of a person than i am because of my race. the star was also degrading for those who had to wear it because they were aware of this and the nazis used the notion to make them feel less like a person.